You're referring to Feena Archwood, I suspect.
Feena was the daughter of Maleva. Her mother, knowing that Feena was a werewolf, sent her to mother Dhauna Myritar at Moonshadow Hall, a temple of Selûne in Yhaunn, Sembia. At the temple, she was trained to control her inner wolf and to become an acolyte. In her stay at the temple, she met Mifano, who was a novice and an acolyte with her, a young man with silvery hair who was extremely flirtatious. Velsinore, their elder sister and the priestess in charge of the acolyte dormitory, always gave Feena harder punishments, maybe for the fact that she was a werewolf. Their relationship was always distant but Feena felt a sort of respect towards Velsinore. This respect was for her great devotion and passion towards Selûne.
Neither of her books, Black Wolf or Mistress of the Night were by Salvatore, but both have a brown color scheme and are set in the Forgotten Realms.
Found via a search for "r.a. salvatore" priestess selune, which caught Salvatore's name as a "Readers also enjoyed" section on the Goodreads review for Mistress of the Night.