dead sure

Whenever a man's got a dead sure cinch like that, it's a drag and not a pull!

She's gone, that's dead sure; and if I don't pepper the red rascal that killed her I wish I may be split.

He didn't appear to have moved, but he was dead sure enough—had been for two or three hours, by the feel of him.

If we had only fifteen cents in our pockets, it would be a dead sure thing, according to all the biographers I ever read.

But, all the same, wherever that Sage-Brush Hen was, there was dead sure to be an all-right cyclone.