Let me explain Sai and Ino's love life to everyone who is still saying "I don't know how they ended up together": 💜
People really be jumping to Boruto series without knowing what has happened in the Naruto series after the war arc. Well, here is Sai and Ino's relationship throughout the entire Naruto canon timeline.
Manga readers were surprised to see Sai and Ino married in the last chapter (700) of manga. However, later, the canon novels perfectly described how Ino and Sai ended up together.
First and foremost, Sai and Ino met in the very early episodes of Naruto Shippuden. Ino immediately had a crush on him because he was handsome, also noting that he looked like Sasuke. That is basically Ino, the flirty girl as we know. Just know that having a crush and falling in love is two very different things.
Sai was introduced as a character with no emotions and feelings whatsoever. The reason why he thought Ino is "ugly" in their first interaction was because he didn't know what a real beauty is back then. He had no emotion/feelings, how do u expect him to know beauty? Ironically, despite this, he said the opposite of what he thought at her, "Mrs. Beautiful" - building the foundation of SaiIno (Also Ino being the only person who didnt get insulted by Sai's nicknames.)
So, here Sai thought Ino was ugly and Ino only had a crush on Sai because he resembled Sasuke. Two flaws. Okay, cool. Most of the People know their relationship up to here. But that's not even close to the end of Sai and Ino's relationship before their marriage.
Moving on. As Sai and Ino are both side characters, they had almost no interactions on-screen afterwards, till the Fourth Shinobi World War Arc. In the War, both Ino and Sai had each other in their Infinite Tsukyomi dreams. Ino dreamed of Sasuke and Sai fighting over her and Sai dreamed of Ino, along with his other close friends acknowledging his smile. (Sai's dream was in anime-only).
This proves that both have had interactions off-screen to the point that they were already very close friends before the war began. Morever, their IT dreams reveal that by the war arc, Ino likes Sai as much as Sasuke, and Sai likes Ino complementing him.
That's the end of Naruto: Shippuden manga events.
Now, here comes the era of Novels, in which the romance of characters were covered in details after giving hints in manga. (Note: All Blank Period Novels are approved, illustrated and proof-read by Masashi Kishimoto, the author of the Manga himself). Get ready to hear one of the cutest love stories of Naruto series.
Ino lost her crush on Sasuke long back. She is pretty much not into any relationship. This was until in Shikamaru Hiden events, Ino read a letter which describes Sai's tragedies. Since then Ino wanted to know even more about him than she already does. Ino was sent on a mission with her fellow ninjas to help Shikamaru and save Sai, who has been caught in a very strong genjutsu by some enemies. Her top priority after reading the letter was nothing but to save Sai.
As they confronted the genjutsu-controlled Sai, for some reason Ino believed that she is the only person who could save Sai from that powerful genjutsu. Ino risked her life and used her Shintenshin on Sai, in other words, Ino's soul entered Sai's body. Ino dived deep into his mind but all she could see was darkness and dullness. She didn't give up and tried to find his soul by diving even deeper into his mind. Ino finally found Sai's soul crying deep inside, covered with his memories and darkness. Ino learnt about him, called out for him and showed his soul the path out of his memories and darkness. Ino cleared his mind hence saving him from the darkness. Ino's soul then hugged Sai's soul with a heartfelt smile.
This is the point where Sai achieved his dream, the point where he got his emotions and feelings completely back. This is the first time he felt this much kindness from someone and learned what a true beauty is. When Sai is successfully saved by her, the two wake from Ino's jutsu and instinctively reach for each others hands and Sai expresses his gratefulness to Ino, as her eyes begin to tear up, by affectionately calling her "Thankyou, Miss Beautiful". This time, he truly meant this unlike the first time he called her beautiful. "Idiot" - replied Ino. And this time, Ino fell in love with Sai, not because he resembles Sasuke unlike the first time they met. This interaction was complete opposite of their first meeting. This is how their love story began ladies and gentlemen.
Later, while Ino and Sakura were on a mission together, Ino reveals her love to Sai after what has happened. She was thinking of confessing her love to him properly with a special flower. However, when they returned Konoha, Ino finds out Kakashi has sent Sai alone on a mission. Ino gets worried and questions his safety, and is angry that Kakashi let him go alone. After Sai returned and Sakura got kidnapped, Ino ran to Sai's place to inform his about Sakura's disappearance. When she arrives, she becomes flustered to see Sai only in his underwear, as he was taking a shower right before she came.
Sai and Ino together alone goes on a mission alone to save Sakura. They are the only couple besides Sakura and Sasuke who did a mission together alone. Sai and Ino flew in the sky on a Choju Giga Bird, and Sai comforted Ino as she was scared and had a difficulty maintaining the balance, causing her to feel a sweet warm sensation well up within her heart. They both together infiltrated a hideout. The Saiino duo's teamwork was amazing and flawless.
After Sakura is freed, they had to fight the enemies. Ino, who was usually positioned near the back lines during close ranged combat situations was now instead supporting Sai with her taijutsu and healing Sai's injuries with her medical ninjutsu. Sakura, and Sai himself complements Ino on how well she works work together as a duo with Sai, getting Ino even more flustered. Later Sakura prompted Ino and Sai to have a date dinner together, where Ino possibily confessed him and they started dating.
As usual, Sakura and Ino keeps on fighting and competing, and now Ino takes a lot of pride with her blossoming relationship with Sai, claiming she has better love life and will get married before Sakura, much to Sakura's infuriation. After some days, at Naruto and Hinata's wedding ceremony, Sai and Ino arrived as a dating couple holding hands. Later, Akamaru spotted Sai and Ino on a date and was described as "A couple totally on fire". They were usually spotted on dates afterwards.
SASUKE SHINDEN: BOOK OF SUNRISE
Later, after Ino was hospitalized due to the injuries she had after stopping an invasion, Sai was with her at the hospital all the time. Shikamaru and Chōji decide to visit Ino at the hospital and find that Sai is watching over her whilst she sleeps as he sketches a flower that Ino's mother brought her. Shikamaru and Chōji asks Sai to come with them for some investigation, but Sai remains, claiming that he will leave as soon as he has completed his drawing, however, Shikamaru notices several of Sai's already near-completed sketches in the trash as he exits. Shikamaru and Chōji realize that Sai did not want to leave Ino's side and begin discussing how much he has changed from the emotionless man they first met after Ino and Sai fell in love.
BORUTO MANGA/ANIME AND NEW ERA NOVELS
Ino and Sai later got married and had a wonderful wedding ceremony where Shikamaru and Choji was so happy for Ino that they both cried. Sai and Ino's wedding reception is the only wedding reception to have mentioned after Naruto and Hinata's wedding. Sai is the only male to have taken his spouse's surname upon marriage, being now a part of the great Yamanaka Clan, finally having a family of his own. According to Kakashi, Sai and Ino is the most beautiful couple he could imagine, and they both are so close that it seems they are glued to each other, noting that they are like a picture. Sai and Ino also often gets teased by their friends for how close they are.
The two later had a kid, Inojin Yamanaka. It is believed that Inojin's name is a mixture of Yamanaka Clan's customary name prefix "Ino" and the suffix "jin" is reference to Sai's late brother Shin. Sai has already told his son Inojin how his mother, Ino saved him with her shintenshin and how they fell in love, and Sai uses the same method to calm Ino down (with a hug or affection) when she goes mad or gets upset now. The Family confronted gossips and prejudice from villagers and Ino's relationship with Sai was not well received by the Yamanaka Clan, all due to Sai's dark past in Anbu. Despite all this, they managed to be as happy as ever. It is when he married to Ino and got to hold Inojin in his arms, Sai finally felt free and got control over his own life after years of being a puppet to Danzo. Boruto notes that Sai's only weakness is when it comes to Aunt Ino. Sai has never forgotten their anniversary through out more than a decade they have already spent together. Although Ino remains as boisterous as ever, Sai is the sole person that gets Ino to fluster despite how angry or upset she is. Ino is thankful that she didn't end up with Sasuke (Her childhood crush), because now she feels bad for Sakura, whose husband, Sasuke visits her only very rarely. She is thankful for Sai, so is Sai for Ino.
I do not think this much of content, especially for a side-couple is less at all. It's more than enough, It's explained perfectly well. Only people who aren't having an idea on Naruto complete series will question or doubt SaiIno's relationship. So "Random couple", "Ino likes Sasuke because he looks like Sasuke", "Sai is a Sasuke rebound" arguments are all nothing but total crap and bullshit, proved in After-War Novels.
And for those who says Sai and Ino don't have Chemistry..
Sai was an emotionless and socially awkward boy who worked in the Root Section, meanwhile Ino is a emotional and lively sociable girl working at a flower Shop, What else do you see other than the raging chemistry between our root and flower? It has everything. They both are perfect for each other. Ino gave colours to Sai's black & white life. Sai and Ino is the most affectionate couple who has shown most PDA content so far. There, its done.
I hope its clear how they ended up together now 💕💓💖