substantiate vs affirm

substantiate and affirm both are verbs.

Word	Noun	Adjective	Verb	Adverb
substantiate	No	No	Yes	No
affirm	No	No	Yes	No

As verbs, substantiate and affirm are synonyms defined as:

substantiate and affirm: establish or strengthen as with new evidence or facts

Other synonyms of substantiate include confirm, corroborate, support, sustain.

substantiate (verb)	affirm (verb)
solidify, firm, or strengthen	establish or strengthen as with new evidence or facts
establish or strengthen as with new evidence or facts	to declare or affirm solemnly and formally as true
make real or concrete; give reality or substance to	say yes to
represent in bodily form