I think twilight and Megatron being a messy weird couple would fix something in me tbh. Rip to Equestria the moment a sneaky pic of her majesty making out with giant metal beau gets out to the presses though.
as much as I would loveloveloveLOVE the inevitable cutie mark crusader's episode where they scramble to stop that photo from making it to the presses(And are scarred for life in the process), I honestly think leaking evidence is the only way to legitimize their relationship.
If they made some bigass sweeping announcement about it like they did with her inauguration or like, Cadence and Shining Armor's engagement or w/e, no one would ever believe they were actually into each other. They're not convincing anyone this wasn't a political move to stop the decepticons from invading and partially cyberforming Equestria. Her highness is noble as fuck, she wouldn't bat a goddamn eye over a political marriage to keep her people safe and avoid war. No one is gonna believe they actually give a shit about each other for the rest of their lives(Which, considering both the cybertronian and equestrian-princess lifespan, is basically eternity.)
But if they get caught? If there's photo evidence oh him giving her backshots in the royal pantry at 3:45 AM, going to Donut Joe's later, and him subsequently purging into the dumpster behind Donut Joes bc he can't digest horse food? Equestrians are forced to accept that their princess likes them as big and nasty as they come, and decepticons have to grapple with their leader getting down on all fours and rolling over for a taste of that sparkliest sparklehorse that ever sparkled's puthy.