noun, noun which may take the genitive case particle 'no'
one's heart; one's mind; one's inner thoughts
Refers to what one truly feels or thinks inside, often used in expressions like 胸中を明かす (to reveal one's true feelings) or 胸中を察する (to understand someone's feelings).
He rarely reveals what's on his mind.
彼女の胸中は複雑だった。
Her feelings were complicated.
He finally revealed his true feelings.
Sensing what my friend was feeling inside, I didn't ask anything.
After the game, the coach spoke frankly about what was on his mind.
Although he won the championship, his feelings inside were complicated.