Fury said he does not "fear" compatriot and WBA, IBF and WBO champion Anthony Joshua or WBC title-holder Wilder. "He wants to be the undisputed heavyweight champion of the world".
This follows a well-publicised projection from Hearn that the bout could gross well over £100 million from ticket sales and pay-per-view costs.
Hearn, who is in NY for talks with the Wilder camp on Friday, acknowledged he received an email from Wilder confirming the big-money pledge, but Joshua's promoter will not take it seriously until he has proof the funds are in place. "I wanted to prove him wrong".
When asked about the status of the current offer, AJ's promoter continued: "We haven't even seen any paperwork yet so we're gonna request that and we're gonna explore it". Originally Wilder was fine with coming to the United Kingdom for a stadium fight against Joshua in the late summer.
However, Joshua's promoter Eddie Hearn said earlier this month that the WBA has ordered the Briton to enter into negotiations with mandatory challenger Alexander Povetkin.
Deontay Wilder's co-manager Shelly Finkel says they have offered a $50m "take it or leave it" offer to fight Anthony Joshua, and want a response within 24 hours.
The 28-year-old Joshua (21-0, 20 KOs) won a world title in 2016 and has made five defenses, including unifying three belts with a decision win against Joseph Parker on March 31 in Cardiff, Wales.
He added that he would not rule out allowing Wilder's team to pick the fight's date and location as both fighters and their advisers are scheduled to meet on Friday. "It has to be the next fight for each of them".
"And by the way, all the money is in the bag so I expect you to be a man of your word". "If it is there and up front, it is held and secure, it is definitely something we are going to look at".
"If you've got it, show it to us and then we can talk, " Hearn, who is in NY for a Matchroom Boxing USA card and will meet Wilder's representatives on Friday, " said". We need to see a contract.
Lou DiBella, who has promoted many of Wilder's recent fights working closely with adviser Al Haymon, told BoxingScene.com on Wednesday that Wilder's counter offer proves just how much they value Joshua's current standing as the biggest fighter globally in the sport.