vow vs affiance

vow is a noun but affiance is not a noun.

Word	Noun	Adjective	Verb	Adverb
vow	Yes	No	Yes	No
affiance	No	No	Yes	No

As verbs, affiance is a hyponym of vow; that is, affiance is a word with a more specific, narrower meaning than vow:

Other hyponyms of vow include betroth, engage, plight, profess, swear.

vow (noun)	affiance (noun)
a solemn pledge (to oneself or to another or to a deity) to do something or to behave in a certain manner

vow (verb)	affiance (verb)
make a vow; promise	give to in marriage
dedicate to a deity by a vow