Source : Webster's Revised Unabridged Dictionary (1913)

Amicableness \Am"i*ca*ble*ness\, n.
   The quality of being amicable; amicability.

Source : WordNet®

amicableness
     n 1: a disinclination to quarrel [syn: {amicability}]
     2: having a disposition characterized by warmth and
        friendliness [syn: {amicability}]