What does affiance mean?
The definition of affiance
Af*fi”ance, n.
Etym: [OE. afiaunce trust, confidence, OF. afiance, fr. afier to trust, fr. LL. affidare to trust; ad + fidare to trust, fr. L. fides faith. See Faith, and cf. Affidavit, Affy, Confidence.]

1 Plighted faith; marriage contract or promise.
2 Trust; reliance; faith; confidence. Such feelings promptly yielded to his habitual affiance in the divine love. Sir J. Stephen. Lancelot, my Lancelot, thou in whom I have Most joy and most affiance. Tennyson.

Af*fi”ance, v. t.
[imp. Affianced; p. pr. Affiancing.] Etym: [Cf. OF. afiancier, fr. afiance.]

1 To betroth; to pledge one’s faith to for marriage, or solemnly promise (one’s self or another) in marriage. To me, sad maid, he was affianced. Spenser.
2 To assure by promise. [Obs.] Pope.