How to say 'peace' in Spanish: Paz. You try it.
If you want to say something like 'love, peace, and prosperity', you would say, "Amor, paz, y prosperidad." You try it. Also, if you want to say something like 'world peace', you could say, "La paz mundial." You try it.
Those are 2 different ways to use 'peace' or say 'peace' in Spanish.