Formal:
* Vous êtes tellement... (You are so...) - This is the most formal way to say it.
* Vous êtes si... (You are so...) - Slightly less formal than "tellement" but still polite.
Informal:
* Tu es tellement... (You are so...) - This is used for friends, family, and people you are close to.
* Tu es si... (You are so...) - Similar to "tellement" but more common in casual conversations.
* T'es tellement... (You are so...) - Very informal and used mostly with close friends. It's a shortened version of "Tu es".
* T'es trop... (You are too...) - This emphasizes the degree of something and can be used both positively and negatively.
Examples:
* Vous êtes tellement gentil. (You are so kind.)
* Tu es si belle. (You are so beautiful.)
* T'es trop drôle. (You are too funny.)
Important Note: When using the informal forms, it's important to be mindful of your relationship with the person you are talking to.