Why was the end changed?

Rating: 7/10 (20 May 2006)

I've read the book, a really great one, and since then I had been waiting anxiously to watch the movie. I bought the tickets two weeks in advance and on 19th May there I was.
The beginning of the movie was good. I really thought it would be the best film ever, but when it ended, I just couldn't understand: Why were there so many changes? Why wasn't Saunire Sophie's real grandfather? Why didn't she have a brother? And the most important: Why didn't she kiss Robert Langdon? I was completely disappointed with this lack of romance. I see no reason for that, even though I know the importance of a script adaptation and the intention of keeping the attention on the mystery about the holy grail and the religious history.