* Amiable: meaning friendly and pleasant.
* Friendly: meaning showing kindness and affection.
* Cordial: meaning warm and friendly.
* Harmonious: meaning characterized by agreement and peace.
* Peaceful: meaning free from disturbance or violence.
You could also use phrases like:
* In a state of amity
* Characterized by amity
* Marked by amity
The best choice will depend on the specific context of your writing.