Verb confirm, validate
Synonyms: add up, attest, authenticate, bear out, certify, check, check out, check up, check up on, corroborate, debunk, demonstrate, document, double-check, establish, eye, eyeball, find out, hold up, justify, make certain, make sure, pan out, peg, prove, settle, size, size up, stand up, substantiate, support, test, try
Antonyms: discredit, disprove, invalidate