The 23-year-old Wales international produced a scintillating performance on Saturday, scoring both of Spurs' goals as they beat Newcastle 2-1 at White Hart Lane.
Bale, who was deployed in a free role against Alan Pardew's side, has now scored 15 goals this season.
He has been linked with a move away from the club, with both Chelsea and Real Madrid reportedly interested, but Villas-Boas was keen to stress how reluctant Spurs were to let him go, comparing it to the prospect of Ballon d'Or winner Lionel Messi leaving Barcelona.
"Obviously, we have spoken about that at length and are not going to go through it again," said the Portuguese. "Most teams have to hang on to their best players, Barcelona losing Messi would be a disaster, Real Madrid losing Ronaldo would be a disaster so this is exactly the same.
"Teams are dependent on great organisation and also great individuals when
they are able to express their football to the maximum.
"There isn't a release clause in English football, it's very difficult to negotiate with Tottenham as you know and we are not willing to let our best assets go. We can't turn this into a debate every time a player does well."
Villas-Boas wore a T-shirt at his post-match press conference which read
'Get Well Soon Joe', a message to the son of goalkeeping coach Tony Parkes, who was involved in a car crash this week, and dedicated the win to him.
"This is a win we want to dedicate to Tony Parkes and Joe his son, as Joe tries to hang on to his life," he said.
Tottenham are now unbeaten in 10 Premier League matches and are battling hard with Chelsea for third place in the table.