BUENOS AIRES, Argentina -- Former South Carolina Gov. Mark Sanford proposed marriage to his Argentine lover in the same way he has lived since their affair derailed his political career: combining elements of secrecy with unfiltered expressions of love, and a touch of the weird as well. Sanford confirmed Sunday that he's engaged to Maria Belen Chapur, an intensely private divorced woman whose affair with the married Republican father of four children became tabloid news three years ago.

He proposed to her on Wednesday in the Bella Italia Grille, a high-end restaurant in the upscale Palermo neighbourhood, around the corner from Chapur's luxury apartment, the restaurant's manager said Sunday.

The couple have been regular customers at the restaurant, but this time they arrived separately. Sanford arrived first, and considered a table in the main dining room, but then turned it down as too noisy, said the restaurant manager, who gave his name only as Gustavo.

The manager said Sanford settled on a table for two near the door, and left the engagement ring in a small box with one of the waiters, telling him to give it to Chapur when she arrived. Then he hid out in the bathroom for disabled guests, where cracking open the door provides a direct view of the table, and waited for more than an hour before she finally arrived, the manager said.

The waiter then gave Chapur the box, telling her something about winning a prize. She opened it and seemed puzzled to see the ring until Sanford walked up, declared his love and asked her to marry him. She quickly said yes and they kissed and cried, but no one else in the restaurant seemed to notice, the manager said.

"We're very discreet. They are, too. Nobody noticed. They really are private people," said the manager, who declined to give his last name and said protecting his clients was paramount.

Sanford, who was South Carolina's governor from 2003-2011, had been a rising star in the Republican party with presidential aspirations when he disappeared from the state for five days in 2009. Reporters were told he was hiking the Appalachian Trail. But when he returned to South Carolina, Sanford admitted that he was instead in Argentina with Maria Belen Chapur, whom he later called his soul mate.

"I've been unfaithful to my wife. I developed a relationship with what started as a dear, dear friend from Argentina. It began very innocently as I suspect many of these things do, in just a casual email back and forth in advice on one's life there and advice here. But here recently, over this last year, it developed into something much more than that," Sanford said then in explaining the affair.

Sanford's wife, Jenny, divorced him, and his political career was derailed. The affair also prompted impeachment hearings over Sanford's use of state planes, campaign cash and first-class travel. The former South Carolina congressman ended up paying $74,000 in ethics fines and reimbursed the state for the investigation and for travel and personal expenses.

While Sanford professed his love publicly for the woman in Argentina, Chapur never spoke out, issuing just one terse statement asking for privacy.

When asked about the engagement by The Associated Press on Sunday, Sanford simply vouched for the accuracy of a statement released earlier in the day.

"I'd love to talk but we're going to end up in no man's land," Sanford told the AP. "The only comment I'll stand by is that there was a statement sent to CNN and I stand by its accuracy. I don't know anything beyond that."