Sajida Mubarak Atrous al-Rishawi told how she and her husband had carried out the bombing at the Radisson SAS hotel, one of three hotels targeted on Wednesday night in attacks that left 57 people dead.
"My husband wore a belt and put one on me. He taught me how to use it," al-Rishawi said.
Film of her wearing what was reportedly the disabled bomb-belt strapped around her waist were played over parts of her confession.
"We went into the hotel. He [my husband] took a corner and I took another. There was a wedding in the hotel. There were women and children," she said.
"My husband detonated [his bomb] and I tried to explode my belt, but it wouldn't. People fled running and I left running with them."
Al-Rishawi's arrest was announced earlier on Sunday by the Jordanian authorities.
Speaking at a press conference in Amman, Deputy Prime Minister Marwan Muasher said she was the sister of a key aide to al-Qaida's leader in Iraq, Abu Musab al-Zarqawi, a fugitive Jordanian who is Iraq's most wanted man.
Marwan Muasher showed pictures
of the bomb-belt
He said she failed to blow up her explosives charge in the hotel ballroom where a wedding reception was in full swing.
"Her husband asked her to leave the wedding party. Once she did he detonated himself successfully," Muasher added.
He showed pictures of the explosives belt worn by the woman, which he said show "the metal balls that were also attached to the belt so that they can inflict the largest number of casualties".
Muasher said the woman's confession was shown on state TV "to give the Jordanian public some relief, to at least know some details of the operation".
He told CNN that she would be given a fair trial in a Jordanian court, but declined to give any further comments on the investigation, saying it was ongoing.
Also on Sunday, Jordan's King Abdullah II pledged to pursue the ringleaders of the hotel attacks "even if it's beyond the borders of Jordan".
Speaking to NBC's Meet the Press, King Abdullah said the attacks were aimed at ordinary Jordanians.
King Abdullah said Jordan would
pursue the ringleaders
"This was nothing to do with the West. This targeted Jordanian citizens - innocent men, women and children," he said.
The king said Jordan was "suffering from the effects" of the conflict in Iraq, "but we are all hoping, I think as is everybody in the world, that at the end of the day Iraq will be part of the international community".
As the fallout from Wednesday's bombing continues, indications grew of frayed relations relations between Iraq and Jordan, with comments from Iraq's Deputy Prime Minister Ahmed Chalabi condemning the attacks, but alleging Jordan was partly to blame for supporting terrorism in Iraq.
Speaking on CNN's Late Edition Chalabi said: "I wish the Jordanians would take more care to prevent their citizens from coming into Iraq and doing these suicide bombings."