乄陪你到天荒地老乄爱你到沧海桑田
[péi nĭ dào tiān huāng dì lăo ài nĭ dào cāng hăi sāng tián]
These phrases essentially mean staying together with someone forever, no matter how long time passes and how greatly circumstances might change. They express strong promises of loyalty, commitment and everlasting love.