Definition of "affiance"
affiance
verb
third-person singular simple present affiances, present participle affiancing, simple past and past participle affianced
(transitive) To be betrothed to; to promise to marry.
Quotations
[S]he had expected the worst ever since Drusilla had deliberately tried to unsex herself by refusing to feel any natural grief at the death in battle not only of her affianced husband but of her own father [...]
1935 April, William Faulkner, “Skirmish at Sartoris”, in The Unvanquished, New York, N.Y.: Random House, published 1938; republished in The Unvanquished: The Corrected Text, New York, N.Y.: Vintage Books, October 1991, section 1, page 189
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.
2018 July 6, 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
plural affiances
Quotations
All other outward shewes and exterior apparences are common to all religions: As hope, affiance [translating confiance], events, ceremonies, penitence and martyrdome.
1603, Michel de Montaigne, chapter 12, in John Florio, transl., The Essayes […], book II, London: […] Val[entine] Simmes for Edward Blount […]
(archaic) A solemn engagement, especially a pledge of marriage.