General antonyms:
* Friendship
* Love
* Harmony
* Peace
* Unity
* Concord
* Amity
* Fellowship
* Agreement
More specific antonyms depending on context:
* Affection (if the enmity is rooted in personal dislike)
* Respect (if the enmity is rooted in disrespect)
* Trust (if the enmity is rooted in distrust)
* Cooperation (if the enmity is preventing collaboration)
The best antonym for "enmity" depends on the specific situation you are referring to.