Formal:
* J'espère que vous apprécierez ceci. (I hope you enjoy this.)
* Je vous souhaite de bien apprécier ceci. (I wish you to enjoy this.)
Informal:
* J'espère que tu apprécieras ça. (I hope you enjoy this.)
* Bonne dégustation! (Enjoy! - This is a more common way to say "Enjoy this" in French)
* Profite bien! (Enjoy yourself! - This is a more general way to say "Enjoy this" and can also mean "Enjoy the moment".)
The best option depends on your relationship with the person and the situation.