guarantee

Synonyms: agreement assurance attestation bail bargain bond certainty certificate certification charter collateral contract covenant deposit earnest gage guaranty insurance lock oath pawn pipe recognizance security sure thing surety testament token undertaking vow warrant warranty word word of honor

Synonyms: affirm angel answer for assure attest aver back bankroll be surety for bind oneself certify confirm cosign endorse ensure evidence evince get behind give bond grubstake guaranty insure juice maintain make bail make certain make sure mortgage pick up the check pick up the tab protect prove reassure secure sign for stake stand behind stand up for support swear testify vouch for wager warrant witness

Antonyms: break