{adv. phr.} 1. In spite of appearances; at bottom; in reality. * /His manners are rough but he is a kind man at heart./ 2. As a serious interest or concern; as an important aim or goal. * /He has the welfare of the poor at heart./
AT HEART
Meaning of AT HEART in English
Dictionary of English idioms . Словарь английских идиом. 2012