soluble or dispersible?
When something is soluble, it means it will dissolve in the solvent and becomes part of a homogeneous solution. Think of it like salt dissolving in water. If you've dissolved it correctly, you can't see the flecks of salt floating in the water. (The salt is the solute and the water is the solvent.) So if something is a solubilizer, it will dissolve the solute into the solvent and you'll get one homogeneous creation. There is a limit to how much solute can be dissolved in the solvent before a precipitate occurs (the precipitate is the stuff that sinks to the bottom and won't stay in the solution). Each ingredient has a different solubility - salts are very soluble, gold isn't.
There's a funny joke to remember this - If you aren't part of the solution, you're part of the precipitate. Okay, maybe it's only funny to us chemistry geek types!
If you see something that says it's water or oil soluble, that means it will dissolve completely in the water or oil. If you put an oil soluble ingredient into water, you'll see that lovely mass of oil floating at the top pretty soon!
When something is dispersible, it means it will stay suspended in the mixture, but it will always be separate and won't form a homogeneous solution. When we use fragrance or essential oils in something like a body wash, the oils aren't dissolved but suspended. We don't notice a huge difference unless those oils separate out and form an oily mass on top of the body wash, which can happen if you use too much! So if something is a disperser, it means it keeps the ingredients suspended in the product and you won't get a homogeneous solution. You might not notice this - you don't notice a water soluble ester in a body wash because it looks like a homogeneous solution, but there might be tiny little fat molecules that are separate from the actual solution.
Emulsification is a much more complicated process and you can find out more about it here and here.