UNSURE
uncertain, unsure, incertain
(adjective) lacking or indicating lack of confidence or assurance; “uncertain of his convictions”; “unsure of himself and his future”; “moving with uncertain (or unsure) steps”; “an uncertain smile”; “touched the ornaments with uncertain fingers”
diffident, shy, timid, unsure
(adjective) lacking self-confidence; “stood in the doorway diffident and abashed”; “problems that call for bold not timid responses”; “a very unsure young man”
Source: WordNet® 3.1
Etymology
Adjective
unsure (comparative unsurer, superlative unsurest)
uncertain
unstable or precarious
Synonyms
• agnostic (unsure of facts, having no decided opinion on a matter)
Source: Wiktionary