Buddhists: how do you deal with and/or diffuse someone's anger/hatred?

i have no feelings towards this person, other than sadness that they feel so much anger/ hatred towards me. sometimes i think too much about their hatred. it feels like a heaviness in my heart. i want that person to be free from negative feelings. i've tried to make peace with this person but they still express nothing but hatred. how do i not let their negative feelings affect me? i did nothing to this person and i think the root of their hatred is jealousy/narcissism