Many faucets come with a gasket that fits underneath. That usually will keep the faucet from moving if it is tight enough.
Is the slab 2 or 3cm? That will make a difference in how tight you can do things.
Your plumber may hate you, but you could silicon it in place...it won't move once that cures. A razor blade will allow you to scrape off any that gets outside (do it right after you install, and just have the blade vertical - be careful not to scratch the faucet- you could put a piece of tape around it first). If done right, you'll not see any caulk, and it will be a major bear to get the faucet out for repair or replacement!