只为她袖手天下只为他笑面如花
[zhĭ wéi tā xiù shŏu tiān xià zhĭ wéi tā xiào miàn rú huā]
This means 'I give up the world for her, only her smile makes me happy'. The owner of this username may express their devotion and unconditional love towards a certain person. 'Giving the world away just to gain your smile' indicates they would sacrifice everything for that person, which implies profound commitment in a relationship.