confirm vs sustain

confirm and sustain both are verbs.

Word	Noun	Adjective	Verb	Adverb
confirm	No	No	Yes	No
sustain	No	No	Yes	No

As verbs, confirm and sustain are synonyms defined as:

confirm and sustain: establish or strengthen as with new evidence or facts

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

confirm (verb)	sustain (verb)
make more firm	undergo (as of injuries and illnesses)
establish or strengthen as with new evidence or facts	establish or strengthen as with new evidence or facts
strengthen or make more firm	admit as valid
administer the rite of confirmation to	supply with necessities and support
support a person for a position	provide with nourishment
	be the physical support of; carry the weight of
	lengthen or extend in duration or space