testificor Anglais:

Our only witness is refusing to testify.

We noticed his reluctance to testify.

I can testify to that.

She'll never testify against him

To testify is to make a statement or provide evidence, usually in court. Witnesses testify for the prosecution or defense.

The victim didn’t testify at the trial.

I am not in a position to testify.

We speak that we do know, and testify that we have seen; and ye receive not our witness.

And I testify that this is the Son of God.

He came as a witness to testify concerning that light.

You yourselves can testify to what I said.