Peace in a dream generally mean peace in reality indicating agreement, consideration and harmony in your every day living.
Also, peace in a dream may represent inner tranquility, preserving yourself, holding back your actions and being content with control over your thoughts and surroundings.
The peace of mind that comes from relaxing and reflecting on past events is often referred to as the peaceful dreaming state. It has been found to be a time where people are able to resolve conflicts, forget previous worries and even work through learning experiences in their sleep.