@Lily2367
It’s only natural. Affection and love don’t come without reason. Who wants to be with someone who’s clingy and puts their own personal interest over yours? The reason he’s attracted to the current princess is because she’s being thoughtful of him. The previous chapters also made clear he disliked others because of a trauma. That ultimately stems from a fear of betrayal or manipulation. Once he finds someone he actually trusts, which she did with her current action, it’s only natural that he would start to like her presence more. That fear of someone’s invasion of his space will be diminished the more he trusts them.
Also, it’s easier to forgive someone who’s changed than someone who has not. Rather, the fact that he’s even willing to give her another chance despite her previous transgressions is telling of how kind hearted and open minded he is.