你若不走天长地久我不放手白头携手
[nĭ ruò bù zŏu tiān zhăng dì jiŭ wŏ bù fàng shŏu bái tóu xié shŏu]
'If You Don't Leave, I’ll Hold Your Hand Until Old Age' or 'If you don’t leave me, our relationship will last until death do us part.' It expresses deep commitment and unwavering love in a relationship.