Can someone explain to me the end?

Salo,

The literal end of the film is the shot of the arc light in a film projector being extinguished, echoing the sequence of consciously filmic images that opens the film, as well as a similar sequence roughly in the middle of the film. I think those sequences are best understood as referring to images contained in or similar to other Bergman films, and also having the purpose of making clear that the entire film is a consciously cinematic, and thematic, enterprise. By doing so the director is making a parallel point to that made in the general examination of the subject of the persona - how something such as our public face reveals, hides, protects and lets through, as does film. Bergman I think was very conscious of the limitations of film at the same time he obviously was involved in and enamored by the power of film to speak to us. (As I have noted before, this point is also made in a scene in The Passion where Josephson's character Elis describes the medium's limitations in terms of his hobby of photography. But I have also viewed Bergman interviews later in his life where he discusses the limitations of the medium of film.)

But you may be more referring to what can be called the end of the narrative portion of the film, specifically when we see the Alma character walk to a location where she is picked up by a bus. This scene has been the subject of great debate, usually breaking down on lines of whether the two main characters are either literally or symbolically the same person, or two sides of the same person. Those who tend to think so I think view this scene usually as some kind of resolution of the conflict and dynamics that went on before it, either in the sense that Elizabeth and Alma are leaving "together" in the person of Alma, or that Elizabeth no longer needs, or has spurned, the Alma side of her personality, leading Alma to "leave", symbolically.

I find the "same person" view of this film unsatisfying and unpersuasive. My preferred interpretation is that they are two distinct people, and that the real meaing of the ending, relating to the overall theme of the film, is that the dynamic between the two characters has led to a point where they both discover that their efforts, specifically more on Alma's part, to "get behind" Elizabeth's persona, to get through it, ultimately failed. Not completely failed, I think, but if the goal was to achieve some kind of harmonic resolution, to find in another person a purely authentic soul unencumbered by a filtering persona, that was not only not achieved, but is not really possible. Alma's departure thus represents an acknowledgement that this was and is the case. In that connection we do not see what happens to Elizabeth, not shown in the scene or in any other that would indicate what specifically happens to her. But we do not see where ALma goes, either. What is important is that the final scene in the narrative shows one of the two leaving, meaning they are not together any longer. Their dynamic, their search for meaning in each other, has ceased. The lack of focus on what happens to the two underscores that the thematic is the focus, and not a plot resolution. The thematic is the "lesson" of the role the persona has in revealing only so much while masking our inner selves. This limitation is specifically referred to in the earlier portion of hte dialogue where Alma insists that Elizabeth recite the word nothing, and what that signifies.

In other words the theme of the film is how our personas reveal only so much, and hide much. The scene showing Alma getting on the bus symbolizes an acceptance on her part of the truth of this overall theme.