Such a layered work; a film not only about the process of an actor coming to terms with a difficult role, but also about a woman coming to terms with the fact that she is getting older.

This is just my completely subjective
interpretation of the film's ending.

Spoilers for the remainder of the review:

Val's disappearance - and I believe it could be argued that Val was a wholly symbolic presence in the film, a representation and/or reminder of Maria's youth, but I'm not behind the argument that she only existed within Maria's imagination as I've heard some argue; her external social life would be inexplicable then.

I merely think that, while her enigmatic disappearance occurred under quite mysterious and abrupt conditions, nothing more complex occurred than her finally deciding to quit her job. She aided in the process of convincing Maria that someone could indeed simply go out on a hike and disappear one day, reinvent themselves - though with the role in mind, an action so much less dramatic than suicide implies a much different frame of mind, and a strength, within the character of Helena.

Once Maria could accept that the character she was becoming may not have been so weak and may have survived the ordeal, she was finally able to see the role with a greater sense of clarity and understanding (and in the process - because the role was so reflective of her own existence - began to transcend from her role as Sigrid, into Helena... not the Helena she was afraid to be, a Helena she was more comfortable being).

With that being said, it's clear from the scene near the end of the film between Maria and Jo-Ann that Maria is still struggling with her transformation and hasn't fully accepted her new role yet, not just in her art, but in her life as well.