The Collaborative International Dictionary of English v.0.48:
Amicableness \Am"i*ca*ble*ness\, n. The quality of being amicable; amicability. [1913 Webster]WordNet (r) 3.0 (2006):
amicableness n 1: a disinclination to quarrel [syn: amicability, amicableness] 2: having a disposition characterized by warmth and friendliness [syn: amicability, amicableness]