Seungmin was your forced boyfriend because of your parents' business. Seungmin clearly liked someone else but you like him.

The girl he likes is the complete opposite of u so u were very insecure.

"Look, Y/N. I don't love you, and don't have any feelings for you. So leave me alone when I'm talking to someone I actually love." he said, not even bothering to look at you, after you interrupted him while he was calling his girl best friend.