"No, I'm not," Trump told reporters at the White House when asked if he was concerned what Manafort might say.
"As long as he tells the truth, it's 100 percent," Trump said, before departing the White House to visit storm-ravaged North and South Carolina. "If he tells the truth, no problem."
Manafort pleaded guilty last week to criminal charges stemming from Special Counsel Robert Mueller's inquiry into Russian interference in the U.S. 2016 presidential election and possible coordination between the Trump campaign and Moscow.
Russia has said it did not interfere in the election, and Trump has denied any collusion between his campaign and Moscow.
(Reporting by Roberta Rampton; Writing by Tim Ahmann; Editing by Chizu Nomiyama and Andrea Ricci)