Trump also gave a 40 percent chance that he would choose his running mate from his former rivals in the race for the nomination.
He said he has a good relationship with John Kasich, but the Ohio governor, who was the last to drop out, is unlikely to be his VP choice. "I not sure John even wants it."
Trump said he prefers to pick a running mate with government experience, because as a businessman he has business issues covered and he'd like help in pushing legislation through.
Sen. Jeff Sessions, who has endorsed Trump, would make a "good anything," Trump said in response to a question of whether the Alabama Republican would make a good VP choice.
Trump said he'd rather run against Democrat Hillary Clinton than against Vermont Sen. Bernie Sanders, saying she's more beatable because she has "so much baggage."
"I'm now watching her fight it out [with Sanders]. She's going to win again because the system is rigged," Trump said. "[Sanders] cannot win, unless she gets indicted."
He said Clinton should be held legally responsible for using a private email sever during her time as secretary of state, but he claimed she's being protected by the Democratic machine and is going to "skate away with it." He called the process a "disgrace."
Trump said he looks forward to the general election debates. With three on the schedule, he said he wishes there were more.
Trump called Obamacare a "total disaster," saying the Affordable Care Act needs to be repealed and replaced. "The country cannot afford it. People cannot afford it. It's good for almost no one."
He said he'd get rid of a numerous regulations that he claims hurt big companies and small businesses alike. "Dodd-Frank has to be either eliminated or changed greatly," he said, adding that the regulators are running the banks.
Trump said he'd also lower taxes, particularly U.S. corporate taxes, which are higher than those of many countries.
Responding to a call by the Rolling Stones for Trump to stop using their music, the billionaire said he uses lots of different songs at his rallies. "I always buy the rights." The Stones said they have not given their permission.