Formal:
* Tu penses (informal, singular "you")
* Vous pensez (formal, singular or plural "you")
Informal:
* Tu crois (informal, singular "you")
* Vous croyez (formal, singular or plural "you")
Example Sentences:
* Tu penses qu'il va pleuvoir? (Do you think it will rain?)
* Vous pensez que c'est une bonne idée? (Do you think it's a good idea?)
* Tu crois qu'il est honnête? (Do you believe he is honest?)
* Vous croyez que c'est possible? (Do you believe that's possible?)
It's important to use the correct conjugation based on the context and the person you are addressing.