你若至死不渝我便生死相依
[nĭ ruò zhì sĭ bù yú wŏ biàn shēng sĭ xiāng yī]
Means 'If you remain unwavering till death, I will cling to life and death with you.' It's an expression of loyalty and commitment to another in relationships or deep friendship, emphasizing unconditional dedication regardless of outcome.