@Zed there are many good reasons for it but regardless of how they've changed from hating her to liking her, it's never comfortable trying to be close to someone thats has been treating you like garbage since birth and she wanted out because the warmth from being in that korean person's family have changed her entire perception and standard of her family.
There might be a feeling of "I want to be back in that body's family since I would rather have them as my real family", or "I would rather be by myself than getting involved with someone else who hated me in the past" that made her that way. Her feeling of "love", not her but the korean person who was in her body, had ruined the concept of love for her in her own world as well since obviously, her boyfriend back on earth is probably so much kinder and more of a gentlemen than everyone here.
There might be a feeling of "I want to be back in that body's family since I would rather have them as my real family", or "I would rather be by myself than getting involved with someone else who hated me in the past" that made her that way. Her feeling of "love", not her but the korean person who was in her body, had ruined the concept of love for her in her own world as well since obviously, her boyfriend back on earth is probably so much kinder and more of a gentlemen than everyone here.
Just a casual reader binge-ing all interesting manhwas that I came across