@PlatinumDisco
This is based on my understanding of otome games from novel (I just can't bring myself to actually play any)
Well, in most otome games, there's a villainess. Who's the fiancee of one of the main targets. That person understandably gets upset with the heroine seducing the target and tries to bully them. They tend to be somewhat prideful, haughty , elegant or anything that's just not trying to flirt, flatter or spend unnecessarily large amounts of time with the target. Partially due to personality, partially due to any possible queen training they might've had.
In comes the heroine. Usually a commoner, or a commoner who's then adopted or otherwise brought into a low-ranking noble house. They appearantly literally bump or run into or just notice the target(s). And then behave... like a very , very weak woman. So weak a breeze could knock them to the ground. This appearantly triggers the protective instincts of the targets, or after some time together they just take to the heroine like an emotional therapist, healing their insecurities or displeasure with their lives.
So then you've got this weak girl they're interested in, and suddenly she becomes harassed by someone. Who could it be ? Why is it happening ? Sometimes it's the actual villainess, sometimes it's their cronies, sometimes someone totally unknown, sometimes it's all a fake act to garner sympathy. And the villainess ? She doesn't feel sad about it. This just raises the target's ire even more in the situation.
Long story short, the targets are either seduced, brainwashed, fooled, extreme idiots to begin with or just swept into emotions. Novels or mangas give various reasons, none of which are really mentioned from the heroine's perspective in those cases where she's actually the MC of the novel / manga, or when she just has a POV briefly.
Then if you take any dating games, extremely few capture targets are married (atleast to my knowledge). Is that just because those games don't feature similar scenarios, because the heroes don't go for married or engaged women or the audience just isn't interested in it ? Who knows.