山盟海誓天长地久永垂不朽海誓山盟甜言蜜语经久不衰
[shān méng hăi shì tiān zhăng dì jiŭ yŏng chuí bù xiŭ hăi shì shān méng tián yán mì yŭ jīng jiŭ bù shuāi]
'Vows That Last As Long As Heaven and Earth' refers to eternal promises and vows like marriage oaths, indicating undying love and commitment which remain beautiful throughout time. However, there’s also a touch of cynicism about empty promises being remembered forever.