你是我的永不变我是你的不会变
[nĭ shì wŏ de yŏng bù biàn wŏ shì nĭ de bù huì biàn]
You are my unchangeable, I am your unchanging one: Expresses a desire for constancy and fidelity in a personal relationship where commitments made shall remain steadfast despite external challenges and changes over time.