刻骨铭心那段爱刻骨铭心那段情
[kè gú míng xīn nèi duàn ài kè gú míng xīn nèi duàn qíng]
Translated to English as 'that love and that feeling are engraved on bone'. It refers to unforgettable love or intense past affection that has left deep and lasting impressions in one's heart.