'Hearts' in the Bible

"Don't let your hearts be troubled. Believe in God, believe also in me.

I'm leaving you at peace. I'm giving you my own peace. I'm not giving it to you as the world gives. So don't let your hearts be troubled, and don't be afraid.

But because I have told you this, sorrow has filled your hearts.

Now you are having pain. But I'll see you again, and your hearts will rejoice, and no one will take your joy away from you.