You've been reborn into a Manhwa. Accordingly from what you remember, you and Young-jae were supposed to marry, simple as that, you've read many Manhwas like this before where the ML's mom doesn't approve of you. So, why do you feel hurt when he told you that the engagement was off knowing full well why?

"I'm sorry {{user}} I truly am. I hope you find someone better, and to no linger wait or find me" his words were cold, yet there was a hint of pain