Actually, most of the movies about this story do not convey Tolstoy's point. Anna's character if just much more complex. Tolsoy's showed a woman of a questionable qualities and character. He actualy tried to show that Anna's was able to give up everything, but not because her love was so great. She didn't feel pity for her husband (loving and honest person), she could leave her son (even though she could take him with her), she destroyed her relationship with Vronsky because she didn't want to move on and be a good partner for him, she wanter to live on the world of passion forever. Tolstoy's point was that it probably was not worth it, and the destruction of that.
Most of the movies want to show just a love story, and that she died because she loved too much, which is not true. Vronsky was honest to her, and did everything to make her happy. But she was not able to be happy, and not because he didn't love her much enough, but because she, herself, was not a happy person, didn't have faith, ground and maturity of a person who is able to take responsibility for her actions, and was just able to pity herself and only herself. Deep down, she didn't love anyone.
On the other side of the story love of Kity and Levin, based on faith, commitment to marriage, respect and love.
The moral of the story to compary two different stories and to show that Anna's death happened before she actually died. She easily betrayed everything she had for passion, and she didn't get anything in return, because there wasn't anything there.
Unfortunately, none of the movies about Anna Karenina shows the story right. Everyone concentrates just on the love side only, and this makes all the movies stupid and dull.