beyond the/a shadow of doubt
With certainty; for sure. I only made such a big change in my life because I knew beyond the shadow of doubt that it was the right thing for me to do. This photo now proves, beyond a shadow of doubt, that my client is innocent. I barely remember leaving the office last night, so I can't say beyond a shadow of doubt that I set the alarm before I left.
without the/a shadow of (a) doubt
With absolute 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.
Farlex Dictionary of Idioms. © 2024 Farlex, Inc, all rights reserved.