You can find the digital version on platforms like Amazon and Goodreads .
The book you are looking for is likely by Blanca Santoro (often confused with the title "Cartas a una dama blanca"). It is a Victorian-era epistolar novel available as an eBook on Amazon . Book Overview Genre: Victorian Romance / Epistolary Novel. Setting: London, 1846.
To fully enjoy this short novel (roughly 70 pages), focus on the following elements:
Since it is epistolary, the entire plot is revealed through the correspondence between the two protagonists.