浮浮夸夸夸出山盟海誓疯疯癫癫癫出天长地久
[fú fú kuā kuā kuā chū shān méng hăi shì fēng fēng diān diān diān chū tiān zhăng dì jiŭ]
'Vows and oaths are easily sworn as if they were everlasting promises, but only true insanity results in eternal happiness.' This conveys that people usually say exaggerated words casually but sincere passion leads to longevity in relationship or friendship.