Meaning of the word "at heart" in English

What does "at heart" mean in English? Explore the meaning, pronunciation, and specific usage of this word with Lingoland.

at heart

US /æt hɑːrt/
UK /æt hɑːt/

Idiom

in one's true character or innermost feelings, as opposed to one's outward appearance or behavior

Example:
He seems tough on the outside, but he's a kind person at heart.
Despite her serious demeanor, she's still a child at heart.