Synonyms for Amiability (same or very similar meaning)
WordNet sense 1 (a cheerful and agreeable mood):
good humor, good humour, good temperWordNet sense 2 (a disposition to be friendly and approachable (easy to talk to)):
affability, bonhomie, geniality, affableness, amiablenessFrom the ODE community, based on WordNetadd/edit