HEROINE
Horse is a street name for Heroin and add E for English and you get HEROINE. The heroine referred to is Elizabeth Bennett in Pride and Prejudice, another of Jane Austen's works.
23d 'Another one' means another term for a sailor (see previous clue) hence SALT and add Ed for Edward and you get SALTED which prevents food going off.
If I were asking for an answer and giving the letters and spaces then no: I would double check that it was correct. Makes the question pretty pointless otherwise, don't you agree?
Furthermore, both questions referred to other clues which weren't given in the post. I don't know about others, but I still haven't mastered this psychic trick yet.