你是我的大世界我是你的小宇宙
[nĭ shì wŏ de dà shì jiè wŏ shì nĭ de xiăo yŭ zhòu]
Translated as “You Are My Whole World, I Am Your Small Universe”, it expresses that the relationship between the two people is vast and encompassing. The user might want to convey deep interdependence and significance in the relationship.