one's heart; one's inner thoughts; one's true feelings
Refers to what one truly thinks or feels inside, often contrasted with outward expression. Common in phrases like 心の内を明かす (reveal one's inner thoughts).
彼はなかなか心の内を見せない。
He rarely shows his true feelings.
心の内を打ち明けられる友達がほしい。
I want a friend I can confide my inner thoughts to.
心中 is a more formal or literary term for 'in one's heart/mind', often used in set phrases. 心の内 is more conversational and emphasizes the hidden inner world.
Standard kanji-kana mixed spelling.
Kana spelling of 内, common in everyday writing.
Ateji-like spelling using 中; the reading こころのうち is irregular for this kanji form. Usually read こころのなか.
Compound of 心 (heart, mind) + の (possessive particle) + 内 (inside). The reading うち for 内 is the native Japanese word for 'inside'.