I don't know who you are yet. But, I hope I like you.
You make her laugh, you challenge her, and you make her a better version of herself. I couldn't ask for more from you.
Thank you for putting up with her so far. We both know that she is a handful, and knows enough to push anyone's buttons, especially yours. You handle it with grace and do so with a smile and a coy laugh, admitting that she is yours and that you are proud to have her.
Never lose that mindset. You are lucky to have her. The minute you lose sight of that, leave. You don't deserve her after that.
She is going to put up with a lot from you. I know you. and I know that you are going to drive her absolutely insane. She is going to call me frantic over your actions quite a lot. But, I promise to remind her what a great guy you are and how blessed she is to have you every time she complains.
Not to be the stereotypical best friend, but if you hurt her, I'll hurt you. You will be loving a heart of gold. If you break her, I break you. Got it? Good.
Now, back to what's important.
She has worked so hard to get to the point in life that she is at now, working through her undergrad. She has been through heartbreaks and high-points, and I have been there for all of them. You haven't. Please understand that you must support her like no other. Don't deter her dreams.
She loves you enough to give them up if you asked her to. Please, don't even think about doing that.
If you love her, you will never ask that of her.
I'm not asking you to change (she fell in love with you for a reason, after all) but please be the best man you can be for her.
She deserves that and more.
She loves you will her entire heart, and then some. You are her world now, and you better make her yours.
The Best Friend (and Maid of Honor)