Formal:
* J'aime Mike. (This is the most common and neutral way to say it.)
Informal:
* Je t'aime, Mike. (This is more intimate and used for a romantic partner or someone you're very close to.)
* J'adore Mike. (This is more passionate and expresses a stronger love.)
* J'aime beaucoup Mike. (This is a less intense way to say you love Mike.)
Important Note:
* In French, the verb "aimer" (to love) can be used for both romantic and platonic love.
* The pronoun "tu" (you) is used for informal situations.
* It's always a good idea to consider the context and your relationship with Mike before choosing how to express your love.