"Reason" was composed by Yoon Jong Shin and written by Park Jin-Young, with English lyrics by Park Jin-Young and An Young-Min. The song was performed by OST, a group created specifically for the drama's soundtrack. The ballad's soaring vocals, poignant lyrics, and sweeping orchestral arrangement have made it a timeless classic in K-pop.
Ultimately, the reason for “Autumn in My Heart” is that some loves are not meant to end in happiness, but in meaning. The English lyrics capture a distinctly Eastern philosophy of Han —a collective grief, a deep-seated sorrow that is not a sickness but a form of beauty. The heart is autumn not because it is cold, but because it is honest. It mourns openly. It colors the world in shades of gold and rust, celebrating the love even as it buries it. reason ost autumn in my heart english lyrics