爱的彻底身不由己
[ài de chè dĭ shēn bù yóu jĭ]
The phrase means being completely submerged in feelings where one cannot control themselves because of the power of their love (Love). Here it expresses the helplessness or intensity of loving to such extent as if one has no choice or will over their own fate, feeling extremely passionate while also losing control of oneself.