"sure shot" is correct and is generally used in spoken English, but is sometimes used in writing as well.
It is used to describe something that is certain to happen or be successful. For example, "My project was a sure shot at the award; I was sure to win."
Here comes a sure shot: Anna Wintour.
I've been using a Leica D-Lux 5, which is a little sure shot, a fantastic camera.
The famous riflewoman Annie Oakley, "Little Sure Shot," gained her fame as a star of Wild West shows.
Not a clear or sure shot, given the danger of Republican filibustering and Democratic wobbliness, but a shot.
He guest features on We Dance Again, Black Coffee's sure shot summer anthem, and also recently became a published author.
Christopher Okupski, the owner of Sure Shot, said he had earlier sold a Honda Accord to Mr. Osbourne.
"Realizing there is not one sure-shot solution, he wanted to lay down a marker," she said.
His name on a book jacket is money in the bank -- which brings us to one of the most sure-shot subjects, money itself.
"The plot opens ever outward for her, her speeding blue convertible a metaphor for the sure-shot arrow of her intellect, the splendidly whizzing shaft of the maiden huntress Diana".
"Iron Man" and "Speed Racer" — the first two entries in the big-ticket season of May through August — both point to the challenge facing a business obsessed with comparisons: last summer's crop of films, driven by an unusual confluence of sure-shot sequels, was so big that this year's more inventive pictures, whether they win or lose individually, may come up short as a group.
The pack contains the Demolition, Sure-Shot and Mountaineer outfits.
