Peace is in inward quiet spirit, not constantly worrying about what will or could possibly happen. Peace is also the kind way we treat others- even when they have done things where we could be mad at them.
is the outward showing of our peace. The face that we are trusting that
God will work things out and, in spite of circumstances, we are content.
I have always felt that there is a strong relation between peace and joy, but I've never known what. I googled it and found the above statement in wiki answers. It is very simple but yet very explaining.