切切底底的老实人透透彻彻的大疯子
[qiè qiè dĭ dĭ de lăo shí rén tòu tòu chè chè de dà fēng zi]
"Totally honest person yet thoroughly big madman" It seems contradictory but might imply a person who appears very earnest and straightforward, yet when driven to extremes (especially by strong emotions) becomes utterly chaotic or irrational beyond description.