[af.fi.ance] n [ME, fr. MF, fr. affier to pledge, trust, fr. ML affidare to pledge, fr. L ad- + (assumed) VL fidare to trust--more at fiance] (14c) archaic: trust, confidence
[2]affiance vt -anced ; -anc.ing (1555): to solemnly promise (oneself or another) in marriage: betroth