know something for a fact

We'll start with two things we do know for a fact.

He knows for a fact that I want him to leave.

And I know for a fact that will mean something to those guys.

I know for a fact that you are not, and never have been, one of us.

What do I actually know for a fact, here, really?

I know for a fact you are working to control the size of the field.

You could go both ways; they knew that for a fact.

Which he knows for a fact she does not spend on the child.

These are things that most of us know for a fact and don't question.

If there is one thing I know for a fact.