"It could happen very, very soon," the Portuguese said. "It's a dream move for him.
"At the moment the two clubs are speaking. I suppose it could go to the last day or it could happen in next two days. But you wouldn't expect the biggest transfer in world football to happen easily."
Villas-Boas added that Spurs will consider fining Bale for not turning up to training for two consecutive days.
"He is involved in a big transfer move to Real Madrid and in the end if it happens, we wish him all the best, but the fact that he hasn't turned up is not the correct behaviour,” he said.
"That is the position they chose to take and it's up to the club to decide if it's a fineable offence.
"I gave the player the weekend off. Monday was a day off for the squad.
"This [transfer] can happen in a different way ... [but] Tottenham will accept most likely the biggest transfer in world football."
Earlier, Bale's camp tried to play down the suggestion that the triple player of the year had become ''furious and frustrated'' with Tottenham's handling of his proposed transfer to Madrid.
Tottenham have previously insisted that they will not sell Bale to Madrid until they have signed at least one more player to replace him. Talks in London are ongoing with Roma over the possible transfer of midfielder Erik Lamela, but Villas-Boas' hopes of being reunited with Zenit St Petersburg forward Hulk look set to be dashed after the club's manager Luciano Spalletti said the Brazilian was not for sale.
Bale has been named in the Wales squad to play in the World Cup qualifiers against Macedonia and Serbia next month.
He has not appeared for Spurs this season, and was pictured in Spain over the weekend. He missed Wales's recent friendly against Ireland due to a foot problem that has troubled him since July.
Aaron Ramsey has also been named in the squad, despite leaving the pitch with a groin injury after scoring both of Arsenal's goals in a 2-0 Champions League play-off victory over Fenerbahce on Wednesday.
Wales, who are 13 points behind Group A leaders Belgium and 10 off second-placed Croatia, play Macedonia in Skopje on September 6, followed by Serbia in Cardiff on September 10.