heart of hearts

plural hearts of hearts

1. idiomaticOne's innermost private feelings.

   She was grieved, and bitterly sorry for the man who was hurt so much. But still, in her heart of hearts, where the love should have burned, there was a blank.

   1913, D[avid] H[erbert] Lawrence, chapter V, in Sons and Lovers, London: Duckworth & Co. […], →OCLC

   2 more examples

   Yet the darling sin is there in our heart of hearts; we hug it close—we hide it from every human eye. But in the still night-watches it comes forth like a serpent out of his hole, and rears its venomous crest, and stings us with the horror of our guilt.

   1876, [Mary Elizabeth Braddon], “At His Door”, in Joshua Haggard’s Daughter […], volume III, London: John Maxwell and Co. […], →OCLC, pages 180–181

   With the "Constance," which in his heart of hearts he loathed, departed the last remnant of Cheyne's millionairedom, and he gave himself up to an energetic idleness.

   1896 November – 1897 May, Rudyard Kipling, chapter X, in “Captains Courageous”, Garden City, N.Y.: Doubleday & Company, published 1897, →OCLC