without a shadow of a doubtbeyond/without a shadow of a doubt
if something is true beyond a shadow of a doubt, there is no doubt that it is true.
This is without a shadow of a doubt the best film I have seen all year.
without the/a shadow of (a) doubt
With certainty; for sure. I only made such a big change in my life because I knew without the shadow of a doubt that it was the right thing for me to do.
without a shadow of a doubt
and beyond the shadow of a doubt
without the smallest amount of doubt. I am certain that I am right, without a shadow of a doubt. I felt the man was guilty beyond the shadow of a doubt.