ok. Alice can c the future, ok?, he meant keep ur future thoughts to ur self.like don't tell Bella wat u see. and it slipped out at the Motel so thats y bella went to the Ballet Studio, cause Alice shared the future to Bella and Jasper.
In Midnight Sun, Alice has a vision of Bella with red eyes and pale skin. This could be one of the thoughts he wants Alice to hide. But, if I remember correctly, Edward doesn't even want Bella to know how vampire's are created, so I think that's probably it in the book. Obviously she already knows in the movie, so the vampire thing is most likely in the film. Hope this helped!