"We're not certain at all what their cash position is," she said.

One can't always be certain at first glimpse, of course.

This was by no means certain at the time the payments were made.

I can't be certain at the moment because they're in deep water.

Indeed, he could be certain that she would tell him, at long last, the truth.

I am not altogether certain at present as to what steps can be taken.

Whether they will or not, we cannot be certain at this point in time.

That was something he could be certain of, at any rate.

But let me tell you there is nothing certain at sea.

She'd certainly paid enough to be certain no one could, at any rate!