sureness vs self-assurance

sureness and self-assurance both are nouns.

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

As nouns, sureness and self-assurance are synonyms defined as:

sureness and self-assurance: freedom from doubt; belief in yourself and your abilities

Other synonyms of sureness include assurance, authority, confidence, self-confidence.

sureness (noun)	self-assurance (noun)
the quality of being steady and unfailing	freedom from doubt; belief in yourself and your abilities
freedom from doubt; belief in yourself and your abilities