In simple words
The heart line is the top line across your palm, starting under your little finger. Palmistry links it with love and feelings.
How to recognise this one: The top line across your palm stays fairly level and does not bend up toward your fingers.
What it means
Your feelings run deep and private. You may find it easier to show love through loyalty and care than to say it out loud, and you are more sensitive than people guess. Reassurance matters to you, and a careless word can stay with you for a long time. Once you trust someone, your devotion is steady and quiet.
Growth
Practise saying one feeling out loud each week, even a small one. People who love you cannot answer what they cannot hear.
Palmistry is a tradition of reflection, not a medical or scientific reading. Lines change over a lifetime, and no line predicts illness or the length of a life.