你的城府太深我无法功入
[nĭ de chéng fŭ tài shēn wŏ wú fă gōng rù]
The literal meaning refers to someone having too many levels of intrigue ('deep stratagem'), making their true feelings hard to read or penetrate, hence 'too deep for me to understand'. This suggests difficulty getting close to someone because of their complex or secretive nature.