What do I say to her?

So here's the story: Well there is a girl I really like and I told my best friend I like her many times. Anyway I asked her to join us at homecoming (at the time she didn't know my friend that well) as she said yes. Well I got sick an told her I couldn't go and offered to watch a movie with her or something but she decided to go with my best friend without me. Then the next weekend they both went to a haunted house together without me. I asked my friend to stop hanging with her without me but he claims there just really good friends and they have "bonded". He is clueless why this upsets me and wants to "settle it like men" at school. So given an answer to a previous question I'm going to call and talk to the girl i like but what do I say to her? Do I tell her I like her?