vow vs betroth

vow is a noun but betroth is not a noun.

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

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

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

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