Final answer:
Parris wants Rebecca Nurse and John Proctor to confess they are witches because he hopes they will implicate others.
Step-by-step explanation:
Parris hopes Rebecca Nurse and John Proctor will confess they are witches because he believes that they will implicate others. As seen in historical records of the Salem Witch Trials, the accusers sought to identify more witches and build their case against them. By implicating others, Parris believed it would strengthen the accusations against those already suspected and give more credibility to the trials.