And no one knows with any certainty what, if anything, works.
The cause of the fire is not known with certainty.
Perhaps no one, not even the leaders themselves, can answer these questions with certainty.
As to the men, I cannot say with certainty who they may have been.
Looking at things other than those I know with certainty will be of interest.
I think those who do so, and with certainty, are the best we have.
All I can say with certainty is what comes next.
The small one moved with certainty, the others had less.
I can see with such certainty exactly what you will say.
The man who had come from the dark moved with certainty.
Idiome