When falsely accused of murder, Rose finds solace in the community of an alchemist. Who better to help her transform her situation than an alchemist? Sydney is a symbol of Rose's need to evolve, which is essentially the whole premise of alchemy, because an alchemist is supposed to take one kind of thing and make it into another, just like they might take natural ingredients to make a potion. Rose is also assisted by a community who understands her and who will fight for her.
Rose's life is one of paranoia and threat of harm, so the plot takes her through one situation to another by way of miraculous escape. Typically, there are arbiters of that escape who are her friends. She seeks to pass through one kind of fate into another one just like a metal passes from one stage to another under an alchemist's watch. The paranoia leaves the reader with an urge for resolution, hoping to see Rose rewarded for her struggle in time.
Ultimately, this struggle leads Rose to be publicly acknowledged for her innocence. When Tasha tries to kill Lissa, she proves more than her innocence. Although the community thought she was a regicidal killer, she is actually a self-sacrificial lover of the throne, and she literally takes a bullet intended for the new queen. The sacrifice is her final stage of evolution, and she survives it. The final stage of her growth is her union with Dimitri, the friend who was always there for her. They are complete, sacrificial people and so their union is one to be celebrated by their community.
