This paper highlights the role of hatred and its evolution in determining the nature of peace between groups, or nations, after reaching, and while implementing, truce. It proposes that weak inertia, diminishing memory of hatred and low propensity to reciprocate hatred are essential for reaching a genuine and stable peace. In the case of mutual abstinence from violence, genuine peace process prevails if both groups have sufficiently weak inertia and strongly diminishing memories of hatred and low proponsities to reciprocate hatred. When these conditions are not satisfied, genuine peace may still be reached if one of the groups has weak inertia and strongly diminishing memory of hatred. Strong inertia, persistent memories of hatred and high propensities to reciprocate hatred are obstacles for reaching genuine and stable peace between groups and nations.