In a speech in Maine on Wednesday, the presumptive Republican presidential nominee said that despite Sanders' criticisms of Trump, the senator, in fact, had a poor relationship with Clinton.
"Bernie, I have to say one thing about Bernie, and he'll be nasty and say 'I'll never vote for Trump.' But I know how he feels inside. He hates her. I mean he cannot stand her. I'm pretty good with people. Bernie Sanders cannot stand Hillary Clinton," Trump said.
See Trump on the campaign trail:
The real-estate mogul also reiterated his agreement with Sanders on trade issues. Trump said that he would renegotiate trade deals like the North American Free Trade Agreement and would pull the US out of the Trans-Pacific Partnership, a multi-national trade agreement that the US is currently considering joining.
"I don't care if they're good, I don't care if they are horrendous, I just want great deals," Trump said.
Over the past several months, Trump has repeatedly suggested that he would co-opt Sanders message in the general election.
In an April interview on MSNBC, the real-estate mogul said he would recycle some of Sanders' rhetorical barbs at Clinton.
"Bernie Sanders has a message that's interesting," Trump said. "I'm going to be taking a lot of the things that Bernie said and using them."
He added: "I can reread some of his speeches and I can get some very good material."
It's unclear whether Trump's claims will win over any Sanders supporters.
In a Washington Post/ABC poll released on Sunday, only 8% of respondents who backed the senator in the Democratic primaries responded that they would support Trump over Clinton in the general election. Last month, 20% of former Sanders supporters said they would back Trump in November's general election.
For his part, Sanders has said he will likely vote for Clinton in the general election. But he's withheld an official endorsement, saying that the former secretary of state needs to embrace more progressive stances on key policy issues.
"I'm going to do everything I can to defeat Donald Trump," Sanders said Sunday in an interview on CNN. "But a lot of that responsibility about winning the American people over to her side is going to rest with Secretary Clinton. We got something like 12 to 13 million votes. And those people voted for me, I believe, because they said it is time to have a president to have to guts to stand up to the big money interests."
He added: "We are saying to Secretary Clinton: Make it clear which side you're on."