The deepest part of oneself. Often used in the phrase "warmed the cockles of (one's) heart." Thank you so much—your kind words really warmed the cockles of my heart.
Fig. to make someone feel warm and happy. It warms the cockles of my heart to hear you say that. Hearing that old song again warmed the cockles of her heart.
if something you see or hear warms the cockles of your heart, it makes you feel happy because it shows that people can be good and kind It's an old-fashioned romance that will warm the cockles of your heart.
Gratify one, make one feel good, as in It warms the cockles of my heart to see them getting along so well. This expression uses a corruption of the Latin name for the heart's ventricles, cochleae cordis. [Second half of 1600s]