I personally like the prince, I wouldn't mind if he and Violet end up together, the prince was not really the bad guy in her previous life, if anything he was pretty merciful of her despite almost killing his beloved bride, and Violet didn't really love him, she was obsessed over him and saw him as an object to attend happiness.
I like Yulian as a person, he is kind and gentle, buuuut I dislike his role as a character, a lot, how the author handle him is messy, Violet had no memory of him after time travel neither is mention of him for the readers POV, I have this "the hell were you before?" sort of feeling every time I see his kind gestures, one could say "well, but she didn't appreciate those gestures before dying so" I still think his role in her previous life is messy.
It really feels as if he didn't exist before, I still think that his role would have being much better if they got close together after her change, to show good things can happen for those who have a change of heart, instead of the childhood friend who always loved her despite being a girl crazy enough to obsess over a guy to the point of wanting to kill the third innocent party, and the guy never had the balls to confess his feelings.
TL;DR: I like Yulian's design and personality but I dislike his childhood friend role in the story.