你说我们要天长地久你说会永远在我左右
[nĭ shuō wŏ men yào tiān zhăng dì jiŭ nĭ shuō huì yŏng yuăn zài wŏ zuŏ yòu]
You promised that we would have a long-lasting love and would stay together forever. It expresses longing and regret over unfulfilled promises of eternal love made by a partner.