that is a bit pessimistic i would say sometimes even if you don't know everything about a person and have fallen for the idea of them later on you could try learning to accept them as who they are
I think the scenario you are describing is a bit too idealistic in nature and in context to the story, it's been pretty evident since the beginning that she has been hooked onto Jaehyun because she is enamoured by the mystery and enigma that surrounds him rather than who he is as a person.
yeah i didn't necessarily say it in context to the story. about the story i understand your opinion means i get it if you want her to move on now even though i don't agree with your mentioned reason there are reasons. but i feel first she needs closure to move on.
She needs to move on from Jaehyun- he isn't the perfect guy she remembered him to be and that's because this is real life where everyone comes with their own problems and issues; he was her crush in the past for a reason because she didn't know anything about him and now that she is getting to know I hope she understands her feelings better and gets over her obsession for him.