He didn't want her because her difficult temperament and bad reputation made her "sister" seem like a better option. They need to get rid of her, because there's a "curse" that will destroy the whole kingdom if she isn't replaced and since she tried to run away, they had no choice (try reading from the beginning and you'll understand better)~Man what the hell😭 dark stuff isn’t good for my heart, stories where someone gets replaced by someone else and everyone is happier are so tragic man.
Also smh that prince didn’t even want her why does she have to die