I'm going to befriend a guy just because I thought his female friend was cute
Do you think he'll be your friend?
I do. I'm good at making friends.
So basically you want to use to guy for his cute friend. It's wrong that you want to use him and you genuinely are not interested making him your friend.
Wtf you're such a jerk. I can make friends with whoever I want!
This is going to be very transparent and the friend will see what you're doing. Not only will not get the friend, but you will make an enemy.