I'm going to tell a girl that likes me that I'm interested in her friend
Why would you tell the girl that?
I want to make her jealous
Purposefully hurting other people is horrible and immoral. You should be flattered the girl likes you and even if the feelings aren't reciprocated, you should treat her with respect and kindness. I highly suggest you rethink your actions.
I'm a troll and I'm just going to do it and get a reaction out of her. Maybe, I'll also try to get a reaction out of her friends.
Won't that make her not like you even more? Your behavior is really erratic just tell her you like her already, she may feel the same way.