4
insistent(adjective, affirmative)
4
never-failing(adjective, strong, complete, flat, firm)
4
no doubt(expression, idiom, certainty, assent)
4
optimistic(adjective, hopeful)
4
palpable(adjective, plain, definite, obvious, distinctive)
4
precisely(adverb, assent)
4
probable(adjective, reasonable, sensible, natural, normal)
4
proven(adjective, test, expert, reliable)
4
purposeful
4
responsible(adjective, good, strong, solid, true)
4
sanguine(calm, strong, certain, definite, wise)
4
self-possessed(adjective, calm, quiet, cool, firm)
4
straight(adjective, close, correct, flat, firm)
4
telling(adjective, energetic, certain, definite, decisive)
4
truly(certainty, assent, affirmation)
4
trusting(adjective, certain, self-assured, assured, self-confident)
4
unafraid(adjective, certain, bold, wise, brave)
4
undeviating(adjective, strong, flat, firm, solid)
4
undoubting(adjective, set, clear, firm, certain)
4
unquestioned
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APASmart Define. (2016). sure thesaurus. Retrieved September 23, 2026, from https://smartdefine.org/sure/thesaurus/synonyms
ChicagoSmart Define. 2016. "sure thesaurus" https://smartdefine.org/sure/thesaurus/synonyms (accessed September 23, 2026).
HarvardSmart Define 2016, sure thesaurus, Smart Define, viewed 23 September, 2026, <https://smartdefine.org/sure/thesaurus/synonyms>.
MLASmart Define. "sure thesaurus" 31 March 2016. Web. 23 September 2026. <https://smartdefine.org/sure/thesaurus/synonyms>