How do you say are the one and only in french?

Here are a few ways to say "you are the one and only" in French, with varying levels of formality and intensity:

Formal/Romantic:

* Tu es l'unique. (You are the unique one.)

* Tu es mon unique amour. (You are my unique love.)

Informal/Romantic:

* Tu es la seule pour moi. (You are the only one for me.)

* Tu es ma seule et unique. (You are my one and only.)

Informal/Playful:

* Tu es mon tout. (You are my everything.)

* Tu es le meilleur. (You are the best.)

More literally:

* Tu es le/la seul(e) et unique. (You are the only and unique.)

The best choice depends on the context and your relationship with the person.