self-assurance vs certain

self-assurance is a noun but certain is not a noun.

Word	Noun	Adjective	Verb	Adverb
self-assurance	Yes	No	No	No
certain	No	Yes	No	No

self-assurance (noun)	certain (noun)
freedom from doubt; belief in yourself and your abilities

self-assurance (adjective)	certain (adjective)
	established beyond doubt or question; definitely known
	having or feeling no doubt or uncertainty; confident and assured
	certain to occur; destined or inevitable
	established irrevocably
	exercising or taking care great enough to bring assurance
	definite but not specified or identified
	reliable in operation or effect