What are sugar-free candies made out of?

A standard hard candy recipe involves lots of sugar, some corn-syrup, and water plus flavors as needed. Without the sugar products, it’s just water, and adding Nutrasweet will just make it sweet water. What magical ingredients do they add to make it solid?

I have a pack of Weight Watcher Fruities here in front of me. Not completely hard, but kind of like Jujubes.

Ingredients: maltitol syrup, gum arabic, water, citric acid, blackberry juice concentrate (adds negligible amount of sugar), glycerin, natural flavor, sodium citrate, artificial flavor, aspartame, acesulfame K.

I’m thinking in this product, it’s the glycerin. In true hard candy, I’m not sure.

It’s the maltitol, a sugar-alcohol, which has many of the properties of sucrose, like the ability to make hard candy, but isn’t metabolized in the same fashion.