胸無城府 [－无－－]

Jyutping hung1 mou4 sing4 fu2
Pinyin xiōng wú chéng fǔ

Definitions (CC-CEDICT)
  1. open and candid (idiom); not hiding anything
  2. ingenuous
Definitions (Wiktionary)
  1. phrase, idiomatic
    to be frank and sincere and not scheming