胸むね三さん寸ずん

noun

heart; mind; feelings

Idiomatic expression referring to one's inner thoughts, emotions, or true intentions, literally 'three inches inside the chest'. Often used in set phrases like 胸三寸に納める (keep to oneself) or 胸三寸で決まる (be decided by one's heart).

• 本ほん当とうの気き持もちは胸むね三さん寸ずんに納おさめておいた。

  I kept my true feelings to myself.

• 成せい功こうするかどうかは、結けっ局きょくは胸むね三さん寸ずんで決きまる。

  Whether you succeed or not ultimately depends on your state of mind.