The important thing is to be exactly sure about what you're doing.

In fact I'm not exactly sure what world it was.

I'm not sure exactly of what, but it was a good thing.

So I wasn't exactly sure what to make of it.

She wasn't exactly sure why, but nothing had ever been more important.

I could never be exactly sure of where he was.

I'm not exactly sure what all those four hundred people do.

Her husband had a lost look in his eyes, as if not exactly sure where he was.

He looks at me, not exactly sure what it is I am trying to say.

Of course, some are not exactly sure who is in the drawing.