Billionaire Donald Trump estimates he acquired the Doonbeg golf club in Clare for €285m (£169m) less than what it was worth.
The property mogul said he reckoned the west Clare estate was worth €300m (£178m) when he tried to buy it four years ago.
The tycoon finally bought it in February, after extensive damage had been caused to it in storms, at the bargain-basement price tag of €15m (£9m). He revealed he even found it hard to believe he was able to get it for that and closed the deal very quickly.
But he said his "big investment" will be what he will spend to make the new rebranded Trump International Golf Links and Hotel "phenomenal".
"If I didn't have confidence in Ireland I would never have made this big investment," he told RTE'.
He has committed to spending at least €45m in expanding the hotel and redeveloping the golf course as well as creating "hundreds of jobs".
But when he bought the Menie Estate in Aberdeen in Scotland over eight years ago he promised to invest about £1bn as well as create 6,000 jobs. So far only £25m has been invested.
The father-of-five and teetotaller, who's been married three times, revealed he instills a strict 'no-drugs, no-alcohol' policy in his children.
O'Rourke also dared ask the question that everyone wants to know: do jokes about his hair bother him? He said: "They kill me. Or at least the people who make them kill me. It used to bother me years ago, but it never stopped."