本音を

one's true feelings

→ 本音
phrase Rare #37,667
one's true feelings 本音 means a person's genuine feelings or thoughts, as opposed to what they say publicly or politely. を marks it as the object of a verb, as in 本音を言う (to speak honestly).
JA: 彼女はようやく本音を話してくれた。
EN: She finally told me how she really felt.

本音を言えよ

Tell me what you really think.

人は本音を隠すものだ

People tend to hide their true feelings.

彼は本音を出した

He spoke his true feelings.

曹操は自分の本音を決して話さない

Cao Cao never reveals what he really thinks.

— レッドクリフ Part I (2008)