Who said best friends couldn't be lovers? Huh? So what if that girl is ugly? Who the heck cares if that girl is tomboyish/plain/nerdy and that guy was utterly popular and was the main topic of fangirls?? Tell me folks, have you ever fallen in love with your best friends? Cause I have. It's the best feeling ever, knowing that someone who knows you're darkest secrets also loves you. 

"Han Chaewon... Listen to me very closely. I, Lee Chanhee, loves you and nothing will ever change that. It never has and it never will."