doubtful vs unsure

doubtful and unsure both are adjectives.

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

doubtful (adjective)	unsure (adjective)
open to doubt or suspicion	lacking or indicating lack of confidence or assurance
fraught with uncertainty or doubt	lacking self-confidence
unsettled in mind or opinion