Promise.

While you guys were in high school,he
had to leave to United States because of his father's work. He promised he would be back and find you.He promised that he would not love another girl. But..he broked it while you kept your promise not to find another guy. That moment got you heartbroken.
'I kept mine, what about yours?'
'Love cannot be forced'
Characters:
You as Jung Jaekyung
Byun Baekhyun
Kim Taeyeon
Park Chanyeol