asseveration vs assertion

asseveration and assertion both are nouns.

Word	Noun	Adjective	Verb	Adverb
asseveration	Yes	No	No	No
assertion	Yes	No	No	No

As nouns, asseveration and assertion are synonyms defined as:

asseveration and assertion: a declaration that is made emphatically (as if no supporting evidence were necessary)

Other synonyms of asseveration include averment.

asseveration (noun)	assertion (noun)
a declaration that is made emphatically (as if no supporting evidence were necessary)	a declaration that is made emphatically (as if no supporting evidence were necessary)
	the act of affirming or asserting or stating something