誓言爱到山崩地裂誓言追到天荒地老
[shì yán ài dào shān bēng dì liè shì yán zhuī dào tiān huāng dì lăo]
This means 'vows of love until mountains collapse and earth breaks, chasing after each other until time ends.' It describes extremely passionate and unwavering romantic dedication and eternal devotion.