The book that gave Mary hope of safely publishing her own story is Memoirs of a Woman of Pleasure (Fanny Hill) – Written by John Cleland in 1748.
The story of an innocent 15 years old country girl who’s forced into prostitution when she arrives in London, this novel was banned for obscenity as recently as 1963, when it was still forbidden in the USA!
(If you'd like to read this masterpiece, click HERE.)
In 1748, when Mary Burton-Gulliver wrote this letter, John Cleland was not – yet - prosecuted for his novel. But just one year later he was arrested, along with his publisher, and forced to renounce the book.
This didn’t stop the book from being secretly printed, circulated and widely read (till today), but the fear of arrest and persecution has probably prevented Mary from publishing her own manuscript.
I imagine that the news of Cleland’s arrest came to Mary as a shock, and she probably then decided to keep her manuscript in hiding.