The Argentine hitman's representatives will try to finalise his hugely-complicated move to Old Trafford within the next week after the deal reached an impasse on Friday night.
The player's agent, Kia Joorabchian, had hoped to announce that a deal was in place already but has been thwarted by the Premier League's insistence that the transfer is conducted through West Ham.
The Hammers threw the proposed move into turmoil by insisting there is no agreement in place for him to join the champions.
But 23-year-old Tevez has given his word to Ferguson that he will join.
He told The People: "Through my backers, I have given my word to Mr Ferguson. They have told him I will be at Manchester United next season and once I make a promise I don't go back on it.
"There isn't a player who would turn down this opportunity and negotiations are too far advanced to go back now."
Tevez knows West Ham fans won't share his enthusiasm for the move, but says he hopes keeping them in the Premier League will temper their anger.
He added: "I hope the fans understand. I had two very good offers from foreign clubs in January but I refused because I had unfinished business.
"It would have been easy to move on, but I couldn't leave the club and the fans in that predicament.
"It will be an emotional and special day whenever I return to play them."