你不懂我怎知我情深
[nĭ bù dŏng wŏ zĕn zhī wŏ qíng shēn]
This translates to 'How would you know my profound love if you don't understand me?' It expresses deep-seated feelings where the person feels unappreciated or misunderstood by their partner, questioning how one can comprehend depth without understanding.