Formal:
* J'espère que tout se passera bien. (This is the most direct and literal translation, and it's appropriate for most situations.)
* Je souhaite que tout se déroule bien. (This is similar to the previous phrase, but slightly more formal.)
Informal:
* J'espère que tout va bien se passer. (This is a slightly more colloquial way to say it.)
* J'espère que tout va bien aller. (This is even more informal and casual.)
Adding emphasis:
* J'espère vraiment que tout va bien se passer. (This adds emphasis and shows you're truly hoping for a positive outcome.)
* Je croise les doigts pour que tout aille bien. (This means "I'm crossing my fingers" and is a more playful way to express your hope.)
The best choice will depend on the context and your relationship with the person you're talking to.