Bale was the recipient of the PFA Players' Player and Young Player of the Year awards last season after a stunning season at White Hart Lane.
Real Madrid have made no secret of their desire to sign the Welshman, but Villas-Boas is adamant he has been given assurances by Daniel Levy that his star man is going nowhere this summer.
Villas-Boas told Portuguese newspaper O Jogo: "The chairman said that we are not open to offers, whatever they are, and that the player will stay.
"In football anything can happen, but these are the guarantees given to me."
Bale scored 26 goals in 44 appearances for Tottenham last season.