How do you say yes marvelous in french?

There isn't a direct translation for "yes marvelous" in French. You would need to choose a phrase depending on the context and emphasis you want to convey:

Formal:

* Oui, c'est magnifique! (Yes, it's magnificent!) - This is a very strong and formal way to express approval.

* Oui, c'est extraordinaire! (Yes, it's extraordinary!) - Similar to "magnifique," but slightly more formal and emphasizes something unique.

* Oui, c'est merveilleux! (Yes, it's marvelous!) - This is a good option for a slightly less formal setting than "magnifique" or "extraordinaire."

Informal:

* Oui, génial! (Yes, great!) - This is a more casual and everyday way to express approval.

* Oui, super! (Yes, super!) - This is a very informal way to say "yes, that's great."

* Oui, parfait! (Yes, perfect!) - This is a good option when you are very happy with something.

You could also use a more specific expression depending on the context, such as:

* Oui, c'est exactement ce que je voulais! (Yes, it's exactly what I wanted!)

* Oui, c'est incroyable! (Yes, it's incredible!)

Ultimately, the best way to say "yes marvelous" in French depends on the situation and your desired level of formality.