The Mexico international has struggled to establish himself at Spurs since joining from Barcelona in 2008 and has made just 10 appearances in the Premier League.
It is almost 12 months since he last featured for Spurs and he has undertaken spells on loan at Ipswich Town, Galatasaray and Racing Santander during his time at White Hart Lane.
He was hoping to secure a move to Sevilla this summer after also being linked with Genoa, Lazio and Wigan Athletic, and is unhappy that Spurs failed to agree a deal.
"To be honest I already felt at another club, Sevilla, and we had already completed more than 50% of negotiations," the 22-year-old told Sport.
"Almost everything had been agreed but with half an hour to go Spurs changed their minds, something I found very odd.
"I was very surprised Harry Redknapp changed his mind, given that in the three years I've been with Tottenham he has not used me or had confidence in me.
"I hope this time he is honest and tells the truth when I talk to him about where he would like me to play.
"Both myself and my agent have been left disappointed, sad and angry at the way Tottenham have acted and after such a long time without having any confidence in me I am now going to get my chance, which seems strange.
"Even so, I mean to take this opportunity out of respect to the Tottenham fans and also because of the professional I am."
Dos Santos has been included in Spurs boss Redknapp's 25-man squad which has been submitted to the Premier League for the first half of the season.