Final answer:
Margaret Paston likely withheld the names of her informants due to fear of repercussions, seeking to protect those individuals from potential harm.
Step-by-step explanation:
From Margaret Paston's statement and the context of the time, the best inference about Paston's purpose in withholding the names of those who warned her to leave is fear of repercussions. During the period in which Margaret Paston lived, disclosing the identities of informants could lead to serious consequences for both the informant and the person sharing the information. It was likely a protective measure to ensure the safety of those involved and to prevent any retaliatory actions from those who might be adversely affected by the information being released.