Synonyms of guaranteed

1 Syllable

iced, sure

2 Syllables

sure-fire, foolproof, pledged, bonded, plighted, cinched, sealed

3 Syllables

endorsed, assured, secured, attested, protected, approved, promised, insured, warranted, certified, affirmed, confirmed

4 Syllables

ascertained, inarguable, open-and-shut

5 Syllables

undisputable, incontestable, establishable, unassailable