I heard this expression in a video when someone was saying to calm down.
It is used to say something like “Put your hand on your heart”.
Is this a question or a contribution to the #dico:ma-missing category ?
In any case, it literally means “to put one’s hand on one’s heart” and it seems to mean something like what you said with perhaps a nuance of ‘Keep your emotions in check’ or ‘Don’t let your emotions get the best of you’.
I ni ce, Malik! Please keep these coming!