uncertain vs unsure

uncertain and unsure both are adjectives.

Word	Noun	Adjective	Verb	Adverb
uncertain	No	Yes	No	No
unsure	No	Yes	No	No

As adjectives, uncertain and unsure are synonyms defined as:

uncertain and unsure: lacking or indicating lack of confidence or assurance

Other synonyms of uncertain include incertain.

uncertain (adjective)	unsure (adjective)
not established beyond doubt; still undecided or unknown	lacking or indicating lack of confidence or assurance
lacking or indicating lack of confidence or assurance	lacking self-confidence
not certain to occur; not inevitable
not established or confirmed
ambiguous (especially in the negative)
not consistent or dependable
subject to change