The "key" to someone's heart is the thing that will make them respond to you positively. The image is of the heart as a locked box and you find the key that will open it emotionally.
To have a heart is to care deeply.
The expression "Have a heart" means "Show some compassion," and it is usually used when someone is demanding too much of another.
Unless there is truly something wrong with your heart, then yes, it is an idiom. My heart fell, my heart exploded, my heart sang, my heart doing anything other than pumping blood is an analogy and an idiom.
It means you feel very strong of someone
Idiom
It is not an idiom. Unkindness is often called heartlessness, and so the expression "have a heart" means "Do not be unkind."
"A heart of stone" is a personification.
It means find that part in the heart, tell what it has, and what it is.
Literally it means that you have a heart, you physically possess that bodily organ.
you have broken somone's heart means to hurt someone feelings.
Unless there is truly something wrong with your heart, then yes, it is an idiom. My heart fell, my heart exploded, my heart sang, my heart doing anything other than pumping blood is an analogy and an idiom.
It means you feel very strong of someone
Idiom
It is not an idiom. Unkindness is often called heartlessness, and so the expression "have a heart" means "Do not be unkind."
It means to feel that there is no way to go on and you just want to give up.
The idiom "made his heart feel heavy" suggests that someone or something has caused emotional pain or sadness. It implies that the person's heart is burdened with negative emotions such as guilt, sorrow, or regret.
"A heart of stone" is a personification.
It is an idiom, because it does not use the term "like" or "as".
The idiom "my heart was in my mouth" means feeling extremely anxious or nervous to the point where it feels like your heart is pounding heavily in your chest.