In Twilight why is it in the book that Edward tells Bella he is a vampire in his car but in the movie the forest?

Answer 1

Any time you translate a book into a movie, changes have to be made to make the story fit into a time allowed for a movie (if they tried to film the whole book, page by page, it would take almost ten hours, just by page count), and sometimes to make it "work" in a visual sense, rather than a verbal sense.

This always involves cutting some details out, or showing them rather than telling about them, and often involves rearranging things to make the visual story flow coherently.

Other than that, Edward doesn't "tell" Bella he's a vampire in either story, he makes her guess, then confirms it.

In the movie, they save time by combining this initial conversation and the famous forest scene into one scene, probably because both scenes deal with Edward revealing more about his nature.