I'm going to ransom a girl's teddy bear
Why would you do that to her? Aren't you in a relationship with this girl?
I've decided that I don't really like her, I just want to get on her nerves.
You shouldn't be ransoming other people's property just to get a kick out of it. What if someone took something important from you just to irk a reaction?
You should understand that I don't like her and I don't care about her teddy bear.
Then you should just leave the teddy bear alone instead of putting ransom towards it that is very inappropriate for you to do specially if you have been invited over their house. If you want, you can go to your local stuffed toy place and see how you can get a new stuffed animal to be friends with.