我爱你到天荒地老我爱你到世界末日
[wŏ ài nĭ dào tiān huāng dì lăo wŏ ài nĭ dào shì jiè mò rì]
It means 'I love you until doomsday', indicating eternal and unwavering love. It expresses the user's intense affection for someone, extending even to an apocalyptic future.