affiance

Etymology

From Middle French affiance, from affier (from Medieval Latin affīdāre, from *fīdāre, from Latin fīdere) + -ance.

verb

1. (transitive) To be betrothed to; to promise to marry.
   She left our former teacher at the altar. Oh well, it's no secret that Prissy was affianced to our former teacher, but justifiably fled the wedding. 6 July 2018, Moira Walley-Beckett, “What We have been Makes Us what We are” (07:00 from the start), in Anne with an E, season 2, episode 9, spoken by Anne Shirley-Cuthbert (Amybeth McNulty)

noun

1. Faith, trust.
   […] in syr Launcelot & you I moost had my Ioye / & myn affyaunce / & now haue I lost my Ioye of you bothe […] […] "in Sir Launcelot and you I most had my joy, and mine affiance, and now have I lost my joy of you both" […] 1485, Thomas Malory, Le Morte Darthur Book XXI, Chapter ii, leaf 421r
   Such feelings promptly yielded to his habitual affiance in the divine love. 1849, James Stephen, Essays in Ecclesiastical Biography
2. (archaic) A solemn engagement, especially a pledge of marriage.