THESAURUS
avouch
acknowledge, admit, affirm, allege, announce, annunciate, argue, assert, assever, asseverate, assure, attest, aver, avow, bear witness, certify, confess, confirm, contend, corroborate, countersign, declare, depone, depose, disclose, enunciate, express, express the belief, give evidence, guarantee, have, hold, insist, issue a manifesto, lay down, maintain, make a promise, manifesto, own, pledge, plight, predicate, proclaim, profess, promise, pronounce, protest, put, put it, say, set down, speak, speak out, speak up, stand for, stand on, state, submit, swear, testify, troth, underwrite, vouch, vow, warrant, witness
ROGET THESAURUS
avouch
Affirmation
VB
assert, make an assertion, have one's say, say, affirm, predicate, declare, state, protest, profess, put forth, put forward, advance, allege, propose, propound, enunciate, broach, set forth, hold out, maintain, contend, pronounce, pretend, depose, depone, aver, avow,
avouch, asseverate, swear, make oath, take one's oath, make an affidavit, swear an affidavit, put in an affidavit, take one's Bible oath, kiss the book, vow, vitam impendere vero, swear till one is black in the face, swear till one is blue in the face, swear till all's blue, be sworn, call Heaven to witness, vouch, warrant, certify, assure, swear by bell book and candle, swear by, insist upon, take one's stand upon, emphasize, lay stress on, assert roundly, assert positively, lay down, lay down the law, raise one's voice, dogmatize, have the last word, rap out, repeat, reassert, reaffirm, announce, acknowledge, attest, adjure.