海誓山盟 [- - shān ménɡ]exchange solemn vows and pledges; lovers pledge of eternal loyalty until the seas dry up and rocks decay; make a solemn pledge [oath] of (eternal) love; Oaths high as the mountains and vows deep as the ocean were exchanged.; plight one's troth; swear by the sea and by the hills; swear inviolable oaths of mutual love and fidelity; swear unchanging fidelity in oaths high as the mountains and deep as the ocean; They swore a great oath that neither would love anyone else.; They swore together an oath of fidelity， vowing never to change until their lives' end.：•¶ 俩人虽未成双, 却也海誓山盟, 私传表记。 Although they had not made love, they had secretly exchanged solemn vows and pledges， bearing their hearts to each other.
•¶海誓山盟, 各无他志。 They vowed solemnly never to love anyone else.