Answer:
The "she" in the line is Abigail Williams.
Elizabeth believes she wants her dead because she (Abigail) loves Proctor and wanted to have him, thus wrongfully accusing Elizabeth Proctor of witchcraft.
This accusation will bring to light the problems within the couple and also bring to light the true character of Abigail Williams and the true nature of the witchery, thus driving the plot to further upheaval with the wrongful imprisonment and convictions of the women of the town and not of the real convicts.
Explanation:
Arthur Miller's <em>The Crucible</em> revolves around the Salem witch trials that overtook the whole town of Salem in the Puritan New England town of Massachusetts. The story involves the wrongful accusations of women by the younger girls in their efforts to escape the punishment that was meant for them.
Elizabeth Proctor's line <em>"She wants me dead I knew all week it would come to this"</em> is a direct accusation of Abigail's false accusation of Elizabeth's involvement in the witchery. The "<em>she</em>" is Abigail Williams and Elizabeth believes "<em>she</em>" wants her dead because she fears that Abigail wants to get rid of her and take her husband Proctor from her. She had known about the affair of her husband with Abigail and had been previously employed by the Proctors.
This accusation will further drive the plot as Abigail's accusations will bring to light the affairs of the whole town, her own affair with Mr. Proctor, and also lead to the wrongful conviction of witchcraft on Elizabeth. And this accusation will bring to light the whole domestic story of the infidelity of Proctor and his lechery. It will also ruin the husband-wife relationship, and also bring out the true nature of Abigail in front of everyone.