The idiom ‘in my heart of hearts’ is a statement of belief in something one strongly believes to the extent of knowing it, even if others disagree that such a belief or piece of knowledge is valid.
One could say ‘In my heart of hearts I know that I am immortal,’ and although everyone else would be sure it was nonsense and the speaker was delusional, the speaker is saying that in spite of the surrounding scepticism she really believes it.
Origin of ‘In my heart of hearts’
The phrase appears in Shakespeare’s play Hamlet, Act 3 Scene 2. It is slightly different from the way the idiom has ended up in that it is ‘heart of heart’ (singular) in Hamlet rather than ‘heart of hearts’ (plural) in the idiom.
In that modern usage the meaning has changed, or developed. When Shakespeare’s Prince Hamlet used it he meant the core – the centre – of his heart. There is a sense in that we still use it like that in its modern usage. When Hamlet says that he will carry a man who is not passion’s slave in the very core of his heart he is saying that he really believes in that man.
Talking to his friend , the only character with whom he is able to communicate in a straightforward way, he says:
“Give me that man
That is not passion’s slave, and I will wear him
In my heart’s core, ay, in my heart of heart,
As I do thee.”
Hamlet Act 3 Scene 2
He is paying tribute to his friend, saying that Horatio is just about the only person he knows who is not governed by his emotions but who is capable of rational thought and that that is something he values above anything else in the people he comes into contact with. Horatio is the only person in the play Hamlet trusts. Because of Hamlet’s different, sometimes bizarre, interactions with the other characters Shakespeare uses the device of the soliloquy to help us understand what’s really in Hamlet’s mind. He also uses Hamlet’s friendship with Horatio, making Horatio his confidant, so that when Hamlet talks to Horatio we know that the things he says are direct, and not the winding up kind of things he says to the other characters.
So he is saying that he will hold such people – like Horatio – in the deepest recesses of his being, deep in the centre of his heart. From that meaning – in the centre of one’s heart – the phrase has evolved to mean having a strong, indelible belief in something.
Synonyms of ‘In my heart of hearts’
inwardly, inside, internally, within, deep down, deep down inside, deep within, at heart, in one’s mind, to oneself privately, secretly, confidentially
Other idioms about the heart
- A big heart: said of someone kind and loving
- A heart of gold: also someone kind and loving
- A heart of stone: said of someone without sympathy
- Break one’s heart: cause someone emotional distress
- Having one’s heart set on: be obsessed with getting something
- Find it in one’s heart: have the compassion or courage to do something
- Harden one’s heart: become unsympathetic
- Heart’s desire: something one wishes deeply for
- Heart of the matter: the essence of something
- Win one’s heart: make someone fall in love with one
- A heavy heart: sadness
- Cross my heart: said as a promise to do something
- Lose heart: become discouraged
- Near to one’s heart: loved or valued by someone
- Gladden the heart: make someone happy
- Heart skips a beat: said of someone excited, frightened, or surprised
- Heart is in the right place: said of someone well-intentioned
- Have someone’s best interests at heart: be doing something for someone else’s benefit
- Hearts and minds: being in full agreement with someone.
- From the bottom of one’s heart: profoundly
- Put one’s heart into: do something with conviction or enthusiasm
- Affairs of the heart: love affairs
- Warm the cockles of one’s heart: cause someone to feel good
- Follow one’s heart: do what one feels like doing rather than what is expected of one
- Heart goes out to: said in regard to feeling sympathy for someone
- Faint of heart: lacking courage
- One’s heart leaps: one is excited
- Open one’s heart: show generosity or kindness
- With all one’s heart: with great enthusiasm
- Young at heart: youthful