After some research, I found that the knife is Freudian symbol to represent sexual want (The Interpretation of Dreams by Sigmund Freud). Therefore, since knifes are used to cut items, such as the bread seen near the beginning of the film. For me, this suggests that she wants to end the relationship with the man, yet, she does not know how to get out of it. The keys on the other hand were used to keep unlocking door, representing an answer to a problem, which was the relationship. I would interpret the dream as she feels guilty because she does not want to part of the relationship. Therefore, subconsciously she feels guilty and the key represents her solution to get out of it. Given the time of the era (1940), where women were not provided all the rights/opportunity to control their own lives. Additionally, this represents her unhappiness in a male dominate society. Her solution to getting out of the relationship is through suicide, seen at the end, which was common in the era since divorce was still taboo.
Lastly, the flower was more abstract for me. Thus, I did some more research on the purpose of flowers in dreams. I found that several interpretations exist, unlike for the knife and key. It may represents the woman 's loss of her sexual identity (since it can be seen falling) or death. I believe it represents death more so given presence of the grim reaper-looking mirrored-faced figure hold