Bale has attracted widespread interest after demonstrating world-class ability during the 2012-13 campaign for Spurs, although he was unable to help them secure a Champions League finish.
Assou-Ekotto admits that it would be difficult to turn down the lure of Spanish giants Real Madrid who are understood to be preparing a world-record £85million bid for the Welshman.
Spurs are prepared to increase the 23-year-old's salary to more than £130,000-a-week and the Cameroon international believes it is the correct thing to do if they want to continue moving in the right direction.
Assou-Ekotto said: "If Tottenham want to have a future and start to be regular in the top four, Tottenham need to keep him.
"I can understand [why he might want to leave]. Real Madrid are not a small club and people know that even if they support Tottenham at 200 per cent."