assertion vs asseveration

assertion and asseveration both are nouns.

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

As nouns, assertion and asseveration are synonyms defined as:

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

Other synonyms of assertion include averment.

assertion (noun)	asseveration (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