Honestly, I feel like going forward, it all depends on how the Prince felt about her. I remember her saying the King disliked her, and the Prince actually liked her and kept denying an engagement with the Saintess.
If the og theory I remember reading is true, and the Sword the Prince stabbed her with was the catalyst to send her back in time (assuming he also used it on himself). Maybe he was trying to let her go knowing that they'd scheme to push the Saintess with him OR after he saw she was making a name for herself. Decided that that could work as clout to get engaged with her without many people bringing up as big of an argument with theSaintess being competition.
My whole rant comes from a bit of dialogue from the 1st chapter.
He could also be completely unrelated or a jerkass seeing as she wasn't in his life this time.
Thanks for the mass release