Final answer:
Proctor decides to confess to witchcraft because he believes it will save his life.
Step-by-step explanation:
When Proctor decides to confess to witchcraft, he is motivated by his belief that it will save his life. In Arthur Miller's play 'The Crucible,' Proctor is faced with the choice of admitting to being a witch or maintaining his innocence, but he ultimately chooses to confess in order to avoid being hanged like the other convicted witches. Proctor's decision is driven by his desire to survive.