Bet That Ruined Him
Genre: romance, campus fiction, enemies-to-lovers, playboy × cold girl, slow burn
Synopsis: He was dared to make her fall. she didn’t even look his way. he still tried. then he fell first—and harder than anyone expected.
WC: 3.4k OR 3,498 words
The entire university knew three things about Lee Heeseung.
First—he was rich.
Second—he was gorgeous.
And third—he never stayed with the same girl for longer than two weeks.
People called him charming. Dangerous. Addictive.
Professors called him “wasted potential.”
His parents called him “difficult.”
His friends?
They called him entertainment.
Because whenever Heeseung walked into a room, something always happened.
───
Friday night.
Music exploded through the walls of the largest fraternity house near campus. Colored lights flashed across drunk students dancing like tomorrow didn’t exist.
Heeseung sat lazily on the kitchen counter with a red cup in one hand, expensive rings shining beneath the neon lights. His dark hair fell perfectly over his forehead despite the chaos around him.
Girls surrounded him.
One touching his arm.
Another laughing too hard at his jokes.
Another asking if he was coming to her apartment after the party.
Heeseung smiled at all of them without really seeing any of them.
Across the room, his best friend Jay snorted.
“You’re actually insane.”
“What did I do now?” Heeseung asked.
“You made that girl cry.”
“I literally told her not to catch feelings.”
Jake laughed from the couch. “That somehow makes it worse.”
Heeseung only shrugged.
Relationships bored him.
People bored him.
Everyone wanted something from him—money, attention, popularity, validation.
Nothing ever felt real.
Then Sunghoon walked into the kitchen with a grin.
“Ohhh,” he said dramatically. “There she is.”
The boys turned toward the front door.
And for the first time that night—
Heeseung looked interested.
A girl walked inside wearing loose black jeans, headphones around her neck, and an oversized gray hoodie like she accidentally wandered into the wrong building.
No makeup except lip balm.
No effort to impress anyone.
No nervousness.
No staring at Heeseung like every other girl did.
She simply walked past him.
Didn’t even glance his way.
Jay blinked. “Did she just ignore you?”
Heeseung smirked faintly. “Cute.”
“That’s Y/N,” Jake said. “Freshman.”
Sunghoon laughed. “The untouchable one.”
“What does that mean?”
“She rejects everyone,” Jay explained. “Athletes. Rich guys. Seniors. Doesn’t care.”
“And she’s kinda mean,” Jake added.
“Not mean,” another student interrupted. “She’s only rude if you’re annoying.”
“Which means all of you.”
Everyone laughed.
Heeseung watched her from across the room.
She sat beside another girl on the couch, calmly sipping soda while chaos happened around her.
Completely unaffected.
Interesting.
Very interesting.
Then Jay made the mistake.
“Bet you can’t pull her.”
Silence.
Heeseung slowly looked at him.
Jay grinned wider. “One month. Make her fall for you.”
Jake immediately groaned. “Bro—”
“What?” Jay laughed. “Heeseung gets every girl. Let’s see if the king survives rejection.”
Heeseung leaned back against the counter.
“What do I get?”
Sunghoon smirked. “Your ego survives.”
“And if I win?”
Jay sighed dramatically. “Fine. I’ll do your statistics project.”
Heeseung’s eyes slid back toward Y/N.
She was laughing softly at something her friend said.
Real laughter.
Not fake party laughter.
Not flirting.
Just… genuine.
Something in his chest pulled strangely.
Still, he smiled lazily.
“Easy.”
───
Monday morning.
Economics lecture hall.
Professor Kang droned on while half the students fought sleep.
Y/N sat near the window with earbuds hidden beneath her hair, sketching tiny doodles in the corner of her notebook.
Then someone slid into the seat beside her.
The entire row looked shocked.
Heeseung.
Of course.
He smelled expensive. Clean cologne and arrogance.
“You’re in my seat,” Y/N said without looking up.
“I don’t think your name is on it.”
“It is spiritually.”
A few students nearby snorted.
Heeseung grinned.
“You always this friendly?”
“You always this jobless?”
That actually caught him off guard.
Most girls giggled around him.
Most tried too hard.
But her voice held genuine annoyance.
Like he was simply inconveniencing her.
Professor Kang looked up. “Mr. Lee. Nice of you to attend for once.”
The class laughed.
Heeseung smiled shamelessly. “I’m trying to become a better student.”
Y/N muttered, “Tragic.”
He heard it.
And for some reason—
He laughed.
Actually laughed.
───
Over the next two weeks, he kept showing up.
Library.
Cafeteria.
Hallways.
Campus café.
At first Y/N assumed it was coincidence.
Then she realized:
No.
He was absolutely following her.
“You’re weird,” she told him one afternoon.
Heeseung walked beside her casually. “You noticed me?”
“I noticed a mosquito too. Doesn’t mean I like it.”
“Ouch.”
But he kept smiling.
Because every conversation with her felt alive.
She didn’t worship him.
Didn’t care about his car.
Didn’t care that girls constantly stared at him.
Once, he picked her up after class in his black luxury car.
Students immediately began whispering.
Y/N climbed in, looked around once, then deadpanned—
“Cool. It drives just like a normal car.”
Heeseung stared at her.
Then burst out laughing.
“Do you enjoy ruining my ego?”
“Yes.”
───
She learned things about him slowly.
That he skipped class constantly.
That he partied almost every night.
That he got into fights when drunk.
That professors expected him to fail despite how intelligent he actually was.
And Heeseung learned things too.
That Y/N worked part-time at a bookstore.
That she sent money home to her mother sometimes.
That she hated fake people more than anything.
That she secretly adored old music and rainy weather.
That she always pretended not to care even when she cared deeply.
One evening, he found her sitting alone outside campus while rain poured around them.
“You’ll get sick,” he said.
She shrugged. “Maybe.”
He stood there awkwardly before sitting beside her under the tiny bus stop roof.
“You don’t talk much at parties,” he noticed.
“I don’t like loud people.”
“You’re talking to one.”
“You’re tolerable sometimes.”
“Sometimes?”
“Don’t get excited.”
He smiled quietly.
Then he noticed her staring at the rain.
Peaceful.
Beautiful.
Not in the glamorous way girls at his parties looked.
Something softer.
Something dangerous.
Because for the first time in years—
Heeseung wanted to stay.
Not chase.
Not win.
Just stay.
───
“Bro, you’re down BAD.”
Jay nearly dropped his fork in the cafeteria.
Heeseung glared. “Shut up.”
“You skipped a party last night.”
Jake looked horrified. “HE skipped a PARTY?”
Sunghoon gasped dramatically. “Call the police.”
“I had class.”
“You’ve never cared before.”
Heeseung ignored them.
But they weren’t wrong.
Things were changing.
He started attending lectures.
Stopped flirting with random girls.
Even his professors noticed.
Professor Kang adjusted his glasses one afternoon.
“Mr. Lee… your assignment was actually excellent.”
The class looked stunned.
Heeseung blinked. “Uh. Thanks?”
Y/N smirked beside him.
“Good job, rich boy.”
“Was that praise?”
“Don’t push it.”
───
Rumors spread fast around campus.
“Heeseung only hangs out with Y/N now.”
“He rejected Mina at the party.”
“He left early last weekend.”
“Did he seriously stop drinking?”
“Apparently Y/N hates smokers too.”
“No way she changed HIM.”
But she did.
Without trying.
Without demanding anything.
He just… wanted to become someone better around her.
Someone real.
───
Then came the problem.
The bet.
At first it had been meaningless.
Funny.
Stupid.
But now every time Heeseung looked at her—
Guilt twisted inside him.
Especially because Y/N trusted him now.
One night, she fell asleep in his apartment while studying.
Curled up on his couch in one of his hoodies.
Heeseung sat nearby staring at her quietly.
His chest hurt.
Because he loved her.
Actually loved her.
And he had built everything on a lie.
───
“You need to tell her,” Jake said seriously.
Heeseung rubbed his face. “I know.”
“She’ll hate me.”
“Probably.”
“Thanks.”
Jay sighed. “Look, man… if she hears it from someone else, it’ll be worse.”
Heeseung knew that too.
And fate apparently hated him because the truth came out the very next day.
───
Y/N walked through campus holding iced coffee when she heard laughter near the basketball court.
“…bro really changed because of a BET—”
She froze.
Her stomach dropped.
Then another voice.
“Heeseung fell first honestly.”
“Still insane he approached her for a dare.”
Everything inside her went cold.
She slowly turned.
The boys noticed her too late.
Silence crashed down.
Jay cursed under his breath.
Y/N’s face became expressionless.
Dangerously expressionless.
Then she walked away.
Fast.
───
Heeseung found her near the music building that evening.
“Y/N—”
“Don’t.”
Her voice was quiet.
That hurt worse than yelling.
He stepped closer carefully. “Please let me explain.”
“You made me a joke?”
“No.”
“A game?”
“It started like that but—”
She laughed once.
A broken laugh.
“Wow.”
His chest tightened painfully.
“Y/N, I swear to you, I love you.”
“You should’ve told me earlier.”
“I was scared.”
“And now I look stupid.”
“You’re not stupid.”
“But you are.”
That hit hard because she was right.
Tears filled her eyes despite how hard she fought them.
“I trusted you.”
Heeseung looked shattered.
“I know.”
“You know what the funny part is?” she whispered. “I actually believed you were different.”
He reached for her hand instinctively.
She stepped back immediately.
“No.”
The look on her face nearly destroyed him.
Not anger.
Disappointment.
“I don’t care that you’re rich,” she said shakily. “I don’t care about your parties or your stupid reputation. I cared about YOU.”
“I care about you too.”
“Then why humiliate me?”
He had no answer.
Because there wasn’t one good enough.
So she left.
And for the first time in his life—
Heeseung felt truly alone.
───
The next weeks were miserable.
He stopped partying completely.
Ignored calls.
Skipped gatherings.
Even his parents noticed.
His mother looked stunned during dinner.
“You’re home.”
His father glanced up from his phone. “And sober.”
Heeseung only muttered, “Can we not?”
For once, there was no arrogance in him.
Just exhaustion.
At university he still saw Y/N sometimes.
But she avoided him completely.
And honestly?
He deserved it.
───
One afternoon Professor Kang stopped Heeseung after class.
“You know,” the older man said calmly, “people can tell when someone changes for real.”
Heeseung looked tired. “Doesn’t matter.”
“It does if you continue changing after losing the person.”
That stayed with him.
Because maybe becoming better shouldn’t depend on whether she forgave him.
Maybe she deserved proof.
Real proof.
Not words.
───
Months passed.
And slowly everyone noticed something shocking:
Heeseung Lee had changed.
Actually changed.
He attended classes consistently.
Helped classmates.
Stopped leading girls on.
Even started volunteering at campus events.
Students whispered constantly.
“What happened to him?”
“Y/N happened.”
───
Winter arrived quietly.
Y/N was leaving the library one evening when she found Heeseung sitting on the stairs outside.
Snow dusted his dark coat.
He stood immediately when he saw her.
“I’ll leave if you want.”
She crossed her arms silently.
He looked nervous.
Actually nervous.
“I just… needed to say this once.”
She didn’t stop him.
So he continued.
“You were right about me.”
His voice was rough.
“I was selfish. Immature. I treated people like games because I never cared enough to stay.” He swallowed hard. “But you made me want to become someone worth staying for.”
Y/N’s expression softened slightly despite herself.
“I know sorry isn’t enough.”
“It isn’t.”
“I know.”
Snow fell quietly around them.
Heeseung looked at her carefully.
“But everything after the bet was real.”
Every word sounded painfully honest.
“The way I waited for your texts. The way I started hating parties because they weren’t fun without you. The way I memorized your coffee order. The way I—”
His voice cracked slightly.
“—the way I loved you.”
Silence.
Then Y/N finally spoke.
“You hurt me a lot.”
Tears filled his eyes instantly.
“I know.”
“And I still don’t fully trust you.”
“That’s okay.”
“But…”
Hope flickered weakly across his face.
She sighed softly.
“I can see you changed.”
Heeseung stared at her like he couldn’t breathe.
“And honestly?” she admitted quietly. “That makes this harder.”
A tiny smile appeared on his face for the first time in months.
“You still care?”
“Unfortunately.”
He laughed weakly through tears.
And for the first time—
Y/N smiled back.
Small.
Shy.
Real.
Maybe not a perfect ending.
Not yet.
But definitely the beginning of something honest.
The strange thing about forgiveness was that it never happened all at once.
It happened slowly.
In stolen conversations after class.
In quiet walks back to the dorms.
In accidental smiles.
In Heeseung waiting outside her lectures just to carry her bag even though she complained the entire time.
“I can carry it myself.”
“I know.”
“Then why are you holding it?”
“Because I like feeling useful.”
“You’re annoying.”
“But you’re smiling.”
Y/N immediately wiped the smile off her face.
Heeseung grinned proudly anyway.
───
Everyone at university was still trying to process the fact that Heeseung had become—
pathetic.
Pathetic for one girl.
Jay almost cried laughing one afternoon when he walked into the student café.
Heeseung was sitting beside Y/N with his chin resting on her shoulder while she studied.
Literally clinging to her.
“Bro,” Jay said in horror. “You used to break hearts.”
“I’m retired.”
Y/N didn’t even look up from her notes. “Unfortunately.”
Heeseung gasped softly. “Baby, that’s mean.”
Jay froze.
Jake froze.
Even Sunghoon nearly choked on his drink.
“BABY?” Jake repeated.
Y/N finally looked up slowly. “Don’t make it weird.”
“You made HIM soft,” Sunghoon accused.
“I didn’t do anything.”
Meanwhile Heeseung looked completely unashamed.
Actually worse—
he looked happy.
Disgustingly happy.
───
He flirted constantly now.
Absolutely constantly.
And unlike before, it wasn’t smooth anymore.
It was clingy.
Whiny.
Cute.
“You look pretty today.”
“I look the same.”
“Still pretty.”
“You need glasses.”
“I need your attention.”
“You’re embarrassing.”
“But you like me.”
Silence.
Then Y/N muttered quietly—
“Maybe a little.”
Heeseung almost fell out of his chair.
───
He became ridiculously affectionate too.
Always touching her somehow.
Holding her sleeve.
Resting his head on her shoulder.
Playing with her fingers during lectures.
Following her around campus like an oversized lost puppy.
One day she finally stopped walking and turned toward him flatly.
“Why are you behind me again?”
Heeseung blinked innocently. “I’m accompanying you.”
“You’ve accompanied me to three buildings already.”
“And I’ll do four more.”
“You don’t have class?”
“I dropped it.”
Y/N stared at him.
“You WHAT?”
“Kidding,” he laughed quickly when she smacked his arm.
But then he pouted dramatically.
“You hit me so much.”
“Because you’re annoying so much.”
“You’re lucky I’m in love with you.”
She rolled her eyes.
Still—
her ears turned slightly pink.
Heeseung noticed immediately and looked way too pleased with himself.
───
Then Heeseung got sick.
And suddenly the entire campus acted like society was collapsing.
Because apparently Lee Heeseung never got sick.
“Probably karma,” Y/N said while reading Jake’s text.
Jake: PLEASE HELP. HE’S DYING.
Sunghoon: He’s been whining for six hours.
Jay: We can’t take it anymore.
Y/N sighed deeply.
Then grabbed her jacket.
───
The Lee mansion was absurdly huge.
Of course it was.
Y/N stood outside the gates looking unimpressed.
“Rich people are ridiculous,” she muttered.
A maid led her inside moments later.
The house looked expensive enough to buy several countries.
Yet somehow—
weirdly lonely.
Before she could think more about it, loud whining echoed from upstairs.
“I DON’T WANT MEDICINE.”
Y/N blinked slowly.
Then another voice.
“Heeseung, you are twenty-one years old.”
“I’m sick, not brave!”
Y/N nearly laughed.
A maid opened the bedroom door.
And there he was.
Messy hair.
Oversized hoodie.
Blanket wrapped around him dramatically.
Pouting.
The second Heeseung saw Y/N, his eyes widened.
“…you came.”
His voice got quieter instantly.
Softer.
And somehow that tiny reaction made something warm spread through her chest.
“Your friends threatened me.”
“They’re evil.”
“You’re dramatic.”
“I’m dying.”
“You have a fever.”
“Exactly.”
Y/N walked closer and pressed a hand to his forehead.
Heeseung immediately melted against her palm.
Actually melted.
His eyes closed slightly.
“…cold hands,” he mumbled.
Y/N ignored the weird flip in her stomach.
“You’re burning up.”
“Stay.”
The way he said it—
quiet.
Sleepy.
Needy.
Made her sigh.
“Fine.”
Heeseung smiled weakly like she had handed him the universe.
───
That was when his parents entered.
His mother stopped immediately.
“Oh.”
His father looked equally surprised.
Because apparently this was the first time in years their son willingly stayed home sick instead of disappearing somewhere.
And now there was a girl beside him.
A girl adjusting his blanket while he stared at her like she hung the moon.
His mother smiled softly.
“You must be Y/N.”
Y/N stood awkwardly. “Hello.”
“We’ve heard a lot about you,” she said warmly.
Heeseung groaned dramatically into his pillow.
“Mom, don’t scare her away.”
His father raised an eyebrow. “Interesting. Usually you scare people away.”
“Dad.”
Y/N accidentally snorted.
Heeseung looked offended.
“You’re supposed to defend me.”
“You’re losing badly.”
───
The medicine battle lasted nearly thirty minutes.
“Take it.”
“No.”
“Heeseung.”
“It smells evil.”
“It’s medicine.”
“I’d rather pass away peacefully.”
Y/N stared at him blankly.
Then suddenly pinched his cheek.
Hard.
“Ow?!”
“Take the medicine, baby.”
His entire face froze.
Red.
Bright red.
Even his parents looked shocked.
Y/N smirked slightly.
“You’re blushing while sick. Impressive.”
Heeseung buried half his face into the blanket.
“…you called me baby.”
His mother immediately looked emotional.
His father looked like he was witnessing a historical event.
Meanwhile Y/N tried not to smile.
“Medicine. Now.”
“…okay.”
His parents almost collapsed from shock.
Because Lee Heeseung had NEVER listened that quickly before.
───
After he recovered, Y/N never let him live it down.
“You cried over cough syrup.”
“I did not cry.”
“You literally said your last words.”
“I was weak.”
“You held my hand like a Victorian child dying from tuberculosis.”
Heeseung whined loudly while following her across campus.
“You’re so mean to me.”
“You survived.”
“Barely.”
Then he suddenly wrapped his arms around her waist from behind.
Students nearby immediately stared.
Because this was still shocking to witness.
Heeseung rested his chin on her shoulder lazily.
“You still took care of me.”
Y/N tried to ignore how warm he felt.
“You would’ve survived without me.”
“Wouldn’t have wanted to.”
And there it was again.
That stupid sincerity.
The thing that always made her heart betray her.
───
He started buying her little things too.
Not expensive flashy gifts.
Not anymore.
Small things.
Things that mattered.
Her favorite snacks.
A hoodie because she kept stealing his.
Books she casually mentioned once.
A tiny keychain shaped like a black cat because “it reminded me of your personality.”
“You’re saying I hiss at people?”
“You hiss emotionally.”
She laughed despite herself.
And Heeseung looked completely mesmerized hearing it.
Like her laughter was still the prettiest thing in the world to him.
───
Then came the date.
A real date.
Not campus studying.
Not random walks.
An actual proper date.
Heeseung had been nervous for three days.
Jay nearly recorded it for blackmail.
“You changed so much it’s scary,” Jake admitted while helping him pick an outfit.
Heeseung frowned into the mirror. “Too much?”
“No,” Sunghoon sighed dramatically. “It’s disgusting but kinda sweet.”
───
The date itself was simple.
Dinner.
Arcade.
Late-night city walk.
Y/N wore a dark oversized sweater and looked unfairly pretty without trying.
Heeseung genuinely forgot how to breathe for a second when he saw her.
“You okay?” she asked.
“…wow.”
“Stop staring.”
“Can’t.”
“Embarrassing.”
“You like it.”
A pause.
“…maybe.”
Heeseung clutched his chest dramatically.
“You’ll actually kill me one day.”
───
Later that evening, while Heeseung ordered drinks at a café counter, a girl approached him.
Pretty.
Confident.
Obviously flirting.
“Hey,” she smiled. “You’re Heeseung, right?”
Heeseung blinked politely. “Uh, yeah.”
“I’ve seen you around campus a lot.”
“Mhm.”
“You should give me your number sometime.”
Before he could even answer—
Y/N appeared beside him.
Completely calm.
“He has a girlfriend.”
Silence.
The girl blinked awkwardly. “Oh.”
Y/N casually slid her hand into Heeseung’s.
“He’s taken.”
The girl apologized quickly before leaving.
And suddenly—
Heeseung stopped functioning.
Completely.
His brain literally short-circuited.
Y/N looked at him. “Why are you staring?”
“…girlfriend?”
“…what, you hate it?”
“No!” he said way too fast.
Then his entire face turned violently red.
Actually red.
Ears.
Neck.
Everything.
Y/N stared for two seconds before bursting into laughter.
“Oh my god.”
“Don’t laugh,” he groaned, covering his face.
“You’re blushing THIS hard?”
“You called me your boyfriend unexpectedly!”
“You practically are.”
“Practically?!”
Y/N rolled her eyes but her grip on his hand tightened slightly.
And Heeseung noticed.
Of course he noticed.
His expression softened instantly.
Then he leaned closer.
“So I’m yours now?”
“You’re clingy.”
“That’s not a no.”
“You’re still annoying.”
“But I’m your annoying boyfriend?”
Y/N looked away to hide her smile.
“…yeah.”
Heeseung genuinely looked like he might faint.
Then suddenly he grabbed her face carefully.
“Okay listen to me very seriously.”
“What now?”
“I don’t want anyone else.”
His voice turned softer.
Honest.
“I only want you.”
The teasing disappeared completely from Y/N’s face.
Heeseung smiled gently.
“So yeah,” he whispered. “We’re kinda stuck with each other now.”
And honestly?
For the first time in a long time—
that sounded perfect to both of them.