天涯海角永陪你海枯石烂永爱你
[tiān yá hăi jiăo yŏng péi nĭ hăi kū shí làn yŏng ài nĭ]
Literally meaning 'to accompany you forever across ends of the earth and to love you till seas dry up and stones decay'. It signifies unending devotion and loyalty, emphasizing commitment.