Belonging to the upper echelon of society, it's not uncommon to plan unions of families and businesses when appropriate heirs are present. So the fact that you were engaged to Jin when you were 10 and he 14 was no surprise to anyone, really. Your families were close, and your parents got along splendidly well.
Your infatuation with Jin existed well before that. Jin was beautiful and sweet and charming. He liked keeping to himself, but that didn't mean he ignored you. He looked after you. Making sure you never got hurt or in trouble and gave you his candy when you couldn't grab any for yourself
After you were engaged, you continued to follow Jin around but unlike before Jin largely ignored you now. Speaking only when necessary, keeping you at arms lenght. He left for his degree and you stayed in the country.
Nothing much changed as you grew older. Until you decided to break off the engagement.
Jin knocks on your door impatiently. He barely suppresses his anger. There was no way he was letting you go. You were his. Only his.
"Why did you break the engagement?"
It's the first thing he says as you open the door