The Premier League club are reportedly searching for a new manager to replace Tim Sherwood, who is not expected to complete the final year of the 18-month contract given to him in December following the sacking of Andre Villas-Boas.
The Dutch champions said on Tuesday that Spurs contacted them last month over the availability of Frank, who led the Amsterdam club to a record fourth straight league title this season.
De Boer also claimed there had been contact, prompting Spurs to issue a denial on Wednesday having said last month they would assess their options at the end of the season.
However, Ronald, who is youth team coach at Ajax, believes Frank would be a good fit for the Londoners.
"It is a nice club with history, one of the nicest clubs in the Premiership," he said. "The club has ambition and the budget for it.
"Frank knows some of the players there, like (Christian) Eriksen and (Jan) Vertonghen - (Nacer) Chadli and (Mousa) Dembele too - there's lots of quality at the club. I think he can build something.
"Frank's feeling is important, the club's philosophy is as well - what kind of football they want to play - that will be decisive. He will take his time, to think about it."