你住我心为什么不交房租
[nĭ zhù wŏ xīn wéi shén me bù jiāo fáng zū]
This translates to 'You live in my heart but why don't you pay rent?'. It expresses that the named person has deeply affected or entered one's inner self or emotions without giving back what they've consumed or influenced, like a person who lives without paying any due. In another meaning, it can also refer to loving someone so much, yet feeling neglected by them.