unsure

Unsure means not certain. You do not know, and you would rather not commit yet.

It takes about or of, or a whole clause: unsure about the date, unsure of himself, unsure whether to go. That middle pattern is worth holding on to, because unsure of yourself means short of confidence rather than short of information, and it describes a person rather than a fact. It is gentler than uncertain, which sounds formal, and much gentler than doubtful, which suggests you suspect something is actually wrong.