asserter vs affirmer

asserter and affirmer both are nouns.

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

As nouns, asserter and affirmer are synonyms defined as:

Other synonyms of asserter include asseverator, avower, declarer.

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