Hey there,
Well, it's nice to finally meet you after I've heard so much about you. And to start off, I want to say thank you for making my best friend so happy. She's one of the greatest people I know and I know you can see that. But I also want to tell you the top three things you should know about your girlfriend's best friend, aka me.
1) We will get to know each other pretty well, and we might even become really close friends, but know that no matter what, I will always choose her. I'm sure you can understand that.
2) I will third-wheel and I hope you're okay with that. Sometimes dinner dates will include me (because who can pass up Olive Garden), but also I know that sometimes you two need alone time.
3) And this is the most important one, so listen closely. I like you because she likes you. I will most likely be the one that she talks to about anything stupid you do, so just know that I will be the best friend who listens and ultimately gives my honest opinion. I am not the best friend who will tell her to stay with someone who doesn't treat her right. I will be the best friend who tells her she should have the best and, most importantly, deserves the best.
You are my new best friend's best friend, so welcome to the club (we meet every Sunday). It's good to see her finally get the cute relationship she has always talked about. And I could not be more ecstatic that I get to listen to the stories of her falling in love. I will try to not get too emotionally involved in your relationship, but it might happen (because I really love all the cute stories, mostly). But I will not be creepy about it, I can promise you that.
I am not the type of best friend to avoid hanging out with you, and will make any effort to get to know you. I think it's important to make you feel welcomed in our friend group, because I know how intimidating we might come off to be. And soon you will be a crucial part of our friend group, so again, welcome.
But just know that if you hurt her, to quote Liam Neeson, I will look for you, I will find you and I will kill you. Okay so maybe not literally, but I think you get the point. I was never blessed to have older or younger sisters, so this girl is the closest thing I have, and I will protect her feelings as much, if not more than my own. But let's hope that never happens.
So, welcome welcome welcome. I am so thankful that you make my best friend so happy.
With all my best,
Your girlfriend's best friend