No mistake

surely; without fail; as, it will happen at the appointed time, and no mistake.

See also: Mistake

References in classic literature ?
Yes, it's a magnificent Roman camp, and no mistake, with gates and ditch and mounds, all as complete as it was twenty years after the strong old rogues left it.
MAKE no mistake, Saturday was a game that Boro lost by making mistakes, rather than one The Hornets won.
Make no mistake, Brendel has created a beautiful album.