Nigerian Adamu has been provisionally suspended while FIFA's ethics committee probes allegations that he and Oceania Football Confederation (OFC) president Reynald Temarii offered to sell their votes when approached by Sunday Times journalists posing as lobbyists for an American consortium.
Fellow executive committee member Temarii has also been suspended in one of the biggest controversies to have rocked football's governing body.
"The ethics committee will investigate this and I am very happy about it because this will enable the whole world to know the truth of the matter," Adamu told the BBC in an interview.
"As far as I am concerned, I am not guilty of what they are saying, but the ethics committee is a committee that is credible and FIFA is a credible organisation.
"I am sure that the whole truth will come out. I welcome it," added Adamu, a former director general of Nigeria's national sports commission.
The newspaper report said Adamu was filmed asking for 500,000 poundsfor a personal project and that Tahitian Temari asked an undercover reporter in Auckland for NZ$3 million ($2.27 million) to fund a sports academy at the OFC's headquarters.
DECEMBER DECISION
Only the 24 members of FIFA's executive committee vote on the World Cup hosts. The decision is due to be made on December 2 in Zurich.
"I'm very, very confident because what was pushed to the public is not a true reflection of what really transpired between me and the journalists," said Adamu, who is banned from all football-related activities while the case is investigated and admitted he was not supposed to comment on it.
"I believe in the credibility of FIFA and the FIFA president (Sepp Blatter), I know that my reputation is intact and the investigation will prove it.
"I'm sure that by the time I come out of this, they will see that I'm a credible person; I believe this investigation will prove it."
Adamu, an executive committee member since 2006, said he did not believe that Blatter was referring to him when the FIFA president said that the world was full of devils, some of whom could be found in football.
"I'm sure when he makes statements he knows what he's talking about. Let's leave it at this," said the former university lecturer.
"This committee will do a thorough job and the whole truth will come out."
England and Russia are bidding to host the 2018 World Cup along with a joint bid from Spain and Portugal while Japan, South Korea, Qatar, United States and Australia are candidates for 2022.
