(as) sure as I'm standing here
Certainly or without a doubt; completely as expected or assumed as true based on previous experience or evidence. It had to have been Mike who leaked our plans to the press, sure as I'm standing here! Come into a great fortune and, sure as I'm standing here, the number of those who would be your friend increases tenfold. The two brothers will be forever at each other's throats, as sure as I'm standing here.
Farlex Dictionary of Idioms. © 2024 Farlex, Inc, all rights reserved.