asseverator vs affirmer

asseverator and affirmer both are nouns.

Word	Noun	Adjective	Verb	Adverb
asseverator	Yes	No	No	No
affirmer	Yes	No	No	No

As nouns, asseverator and affirmer are synonyms defined as:

Other synonyms of asseverator include asserter, avower, declarer.

asseverator (noun)	affirmer (noun)
someone who claims to speak the truth	someone who claims to speak the truth