曾经沧海难为水,除却巫山不是云 céngjīngcānghǎinánwéishuǐchúquèwūshānbùshìyún no rivers compare after the ocean, no clouds compare after Mount Wu
Literally translated as "no water is wide enough after one has seen the great ocean, and no clouds compare to those over Mount Wu." This poetic expression describes having seen the best of something or having experienced a deep love, such that nothing else can ever compare or satisfy.