The noun certitude means certainty or complete assurance.

Synonyms are surenessconfidenceconviction, or inevitability.

The word origins from Middle French (early 14th century) certitude meaning “certainty”, from Late Latin certitudinem meanign “that which is certain”, and from Latin certus meaning “sure, certain”.

We have this definite certitude that our country will flourish under the current administration.

It is impossible to predict a person’s future with absolute certitude.

She promised with certitude as her eyes are glowing with strong determination.