I'm going to shoplift with my bestfriend
Why not just pay for the merchandise?
He doesn't have money and is desperate to get a present for his girlfriend
I understand his girlfriend is very important to him, but stealing is never the right way to do it. Why doesn't he make something hand made instead? She wouldn't like the idea that you had to steal and encouraged him to do so.
She won't know. Though it's possible she won't be happy but she loves him.
I think that stealing is going to upset her and cause problems in their relationship. You should not condone this bad behavior.