谁许谁天荒地老谁许谁地久天长
[shéi xŭ shéi tiān huāng dì lăo shéi xŭ shéi dì jiŭ tiān zhăng]
'Whose promise lasts to eternity? Whose vow lasts forever?' This highlights promises or vows made that people often find hard to keep, especially those concerning eternal love.