guaranteed Synonyms

made sure vouched vested unfailing unexceptionable undisputable underwrote sworn swore suretyship sure stipulated secured secure reliable vouch vowed warrant safeguarded ensured sponsored unhazardous tried and true sure-fire in the bag on ice foolproof confirmed well-tried fail-safe objectified warranted proved promised promise covered countersigned clear certified certificated certain bonded bailed attested assure assured asserted ascertained affirmed decided