What is "sure as eggs"

Usage examples of "sure as eggs".

He'd prefer to be out of Fort Hold altogether on the night of the performance because, sure as eggs cracked, he'd have to go to it.

Shit, sure as eggs Rudgutters got fingers in every fucking pie you can think of.

Because if you don't, then sure as eggs the bastards will kill you.

Just pour it in the water, where it'll float over what you're after, and it'll get him as sure as eggs is eggs.