From Longman Dictionary of Contemporary Englishin your heart (of hearts)in your heart (of hearts)SUREif you know, feel, or believe something in your heart, you are secretly sure about it although you may not admit it In her heart she knew she would never go. Deep in his heart, he wanted Laura back. → heart
Examples from the Corpus
in your heart (of hearts)• They circled frantically in her head and in her heart.• And in her heart she allowed hope to blossom into fragile life again.• All this put a sharp chill in his heart.• Only in memories will Earnhardt return to a place he held deep in his heart.• We are empty in our hearts.• Believe me, we all had a warm place in our hearts for Sidney.• How long must I wrestle with my thoughts and every day have sorrow in my heart?• Never was a boy more overpowered, lonely, and frightened, or carried a greater burden of unhappiness in his heart. 