放不下那抹笑忘不了那段情
[fàng bù xià nèi mŏ xiào wàng bù le nèi duàn qíng]
Translating to 'unable to forget that smile, can't let go of that love story', it evokes memories associated with significant romance - specifically a particular moment filled with emotion and warmth embodied by a specific person's smile.