How do you say I hope have a lovely day in French?

There are a few ways to say "I hope you have a lovely day" in French, depending on the level of formality and the context:

Formal:

* J'espère que vous aurez une agréable journée. (I hope you will have a pleasant day.)

* Je vous souhaite une très bonne journée. (I wish you a very good day.)

Informal:

* J'espère que tu vas passer une belle journée. (I hope you'll have a nice day.)

* Passe une bonne journée! (Have a good day!)

More personal:

* J'espère que tu vas bien aujourd'hui. (I hope you are well today.)

Choosing the right phrase depends on your relationship with the person you're speaking to. For someone you know well, you can use the informal option. For someone you don't know well or for a more formal setting, use the formal option.