I'm going to manipulate my girlfriend
Why would you manipulate your girlfriend?
I believe I own her.
You shouldn't manipulate your girlfriend. Manipulation can lead to psychological issues later on.
She's my servant for gods sake. I have the right to do whatever I want.
I think you're probably joking, but in case you're not: you should not treat a partner like a servant. It's cruel, and chances are that you will get dumped pretty quickly if you don't treat her better.