at heartCHARACTER/PERSONALITYif you are a particular kind of person at heart, that is the kind of person that you really are even though you may appear or behave differently 本质上，心底里；实际上 He may be a working class boy at heart, but his lifestyle has been transformed. 他本质上可能是工人阶级的孩子，但生活方式已经转变。
Let’s face it, we’re all romantics at heart. 面对事实吧，我们本质上都是浪漫的人。
→ have somebody’s (best) interests at heart at interest1(5), → young at heart at young1(5)at heart• Paul was an easy-going fellow at heart who wanted only to enjoy himself.• I guess I'm just a kid at heart.• She's a traveller at heart. You'll never get her to settle down.
→ at heart at heart1(3)