Trump also told Britain's ITV News in an interview to be broadcast Sunday that his administration might not withdraw from the Paris climate accord if terms more favorable to the United States are reached, in part because he likes French President Emmanuel Macron.
The interviewer, veteran British journalist Piers Morgan, told the U.S. leader that Markle backed Democrat Hillary Clinton in the 2016 election and has described Trump as "divisive."
"Well, I still hope they're happy," Trump said.
The interview was conducted Thursday during Trump's brief visit to the World Economic Forum in Davos, Switzerland. In excerpts released earlier by ITV, the president apologized for retweeting videos made by a British far-right group and said he looked forward to visiting Britain, where he has been invited to make a state visit hosted by Queen Elizabeth II.
The guest list for Harry and Markle's May 19 wedding at Windsor Castle has not been made public. The prince's press team said invitations have not been sent out yet. It is not clear if a final list has been drawn up.
The British press has been filled with speculation that Harry might snub Trump and invite former U.S. President Barack Obama as a wedding guest. The prince and Obama have met on several occasions, and Obama gave Harry a rare interview last year that was broadcast on the BBC.
Trump, in contrast, has angered many people in Britain with his crackdown on immigration and his climate change policies.
During his interview with Morgan, Trump deflected a question asking if he would like to attend the wedding festivities at St. George's Chapel, saying only that he hoped the couple is happy.
He seemed open to revisiting his pledge to withdraw from 2015 Paris climate accord if the deal could be substantially revised. Under the pact, nations set their own goals to reduce the emissions of heat-trapping gases. Because of legal technicalities America can't get out until November of 2020
"If somebody said, go back into the Paris accord, it would have to be a completely different deal because we had a horrible deal," Trump said in the interview.
"Would I go back in? Yeah, I'd go back in. I like, as you know, I like Emmanuel (Macron). I would love to, but it's got to be a good deal for the United States."
Trump said the climate has been cooling as well as warming and asserted that ice caps have not been shrinking as predicted.
"The ice caps were going to melt, they were going to be gone by now, but now they're setting records," he said.
However, those remarks don't quite match what data shows and scientists say. The world hasn't been cooling except for normal day-to-day weather variations; it has been just the opposite. And there have been far more records for shrinking ice on the top and the bottom of the world than growing, despite what the president claimed.
