Formal:
* Assez bien: This is the most common and literal translation, meaning "enough well".
* Passablement bien: Slightly more formal than "assez bien", meaning "acceptably well".
Informal:
* Pas mal: This is a very common and casual way to say "not bad", implying something is "fairly well".
* Bien, dans l'ensemble: This translates to "well, overall", and is a good way to say that something is generally okay.
* Ça va: This means "it's going", and can be used to say that things are "fairly well" in a casual setting.
Here are some examples:
* "Comment allez-vous?" - "Assez bien, merci." (How are you? - Fairly well, thank you.)
* "J'ai bien dormi." - "Pas mal!" (I slept well. - Not bad!)
* "Comment s'est passé l'examen?" - "Bien, dans l'ensemble." (How did the exam go? - Well, overall.)
Choosing the best translation depends on the situation and your level of formality.