amābilitas, ātis, f.
amabilis, loveliness, amiableness (only ante- and postclass.): si amabilitas nostra tibi placet, Plaut. Stich. 5, 4, 58: qui amabilitati animum adiceret, devoted himself to loveliness, id. Poen. 5, 4, 1.
—Hence in late Latin as a term of endearment: ad amabilitatem tuam litteras mitto, to your Amiability, Symm. 7, 3.