你是我的天长你是我的地久
[nĭ shì wŏ de tiān zhăng nĭ shì wŏ de dì jiŭ]
'You are my forever and always,' meaning 'you constitute both endlessness (heaven-long) and perpetuity(earth-old).' Expresses undying love or dedication towards someone cherished, emphasizing depth in relationship.