口是心非你读不懂物是人非我猜不透
[kŏu shì xīn fēi nĭ dú bù dŏng wù shì rén fēi wŏ cāi bù tòu]
Combining two classic Chinese idioms: 'Your words don’t match your thoughts' and 'Things change but people are unpredictable,' it describes situations where understanding another’s mind is nearly impossible due to changing circumstances and deceptive intentions.