"If we didn't get it," he told ABC News, "I think we'd have to think very carefully on whether we want to continue with the project."
But on the plateau overlooking the sand dome, Trump's new neighbors do not care much for golf.
David Milne bought his house 15 years ago and has recently finished building a sun deck, from which he was hoping to enjoy the natural vista, and not the swing of rich Londoners and their friends.
"I am busy extending my house with a view to live in here for the rest of my life," he told ABC News.
Milne is one of six owners whose land lies between the proposed golf course and the housing development project.
"They want to build these atrocious building, these time-share flats," he said, "but they are just behind my house."
In order to organize Menie Links residents against the Trump development plan, Milne has created a Web site, www.meniescotland.co.uk, in which he states that the plan is "inappropriate, and is an indication of how insensitive to the Aberdeenshire coast the Trump organisation is."
"The sand dome is a very specific, very rare site in the U.K.," he told ABC News. "If you damage it by stabilizing it, it is after all dynamic and mobile, so you kill it."
Like Forbes, Milne said he is categorical about his refusal to sell. In any case, he said Trump's offers have been derisory.
"I received a written offer about two weeks ago, equivalent to the sales price of a one-bedroom apartment in Aberdeen," he said.
Like him, he said, his neighbors have received offers in the region of $300,000 to $350,000.
"There is no reason for us to sell," he added.
If the price was right, Norman Davidson thinks more residents would be willing to relocate.
"He's got to offer them realistic prices for their property," he said, "because they have to buy houses afterwards, and properties."
"In the first meeting in 2006, they told us they only wanted to be good neighbors," said Milne. "They haven't shown that. The only way for them to be good neighbors now is to leave."
Despite his neighbors' suspicions, Trump had reassuring words for the Menie community.
"I believe that we have the ability in terms of the land and in terms of the location, and in terms of Scotland and in terms of my willingness to commit a tremendous amount of money, to build the greatest golf course anywhere in the world," he said.
Reassuring the press, he reminded them of a former controversial development plan of his, the Trump World Tower in New York City.
"People fought, they were picketing, they were this, they were that. Now many of the people live in the building," he said. "They love it."
But Forbes won't move into one of Trump's houses, even if it means living on an island, surrounded by "Slippery Sam and the gang."
"It's mine," he said, smiling. "It's my island."