Former GOP presidential candidate Mitt Romney spoke to Chris Wallace on "Fox News Sunday" in an exclusive, wide-ranging interview.

Romney weighed in on the 2016 field, including the entry of Hillary Clinton and how he believes that the polls show how the American people don't trust her.

"Hillary Clinton is just not trustworthy," Romney said. "This whole story about her having erased all of her emails, even though they were subject to recall and review by Congress, I think that's made people remember that with the Clintons, it's always something."

Romney added that Clinton has been in power a long time, she's "a creature of Washington."

"How many years does she say? 18 years she hasn't driven a car? She's been driven by Secret Service and other security. I mean, she's been there a long time," Romney said. "I think people want to see real change, want to see something new, and Hillary Clinton is just not that person."

Romney said the real challenge that Clinton will have on the campaign trail is trying to run away from foreign policy. He noted that the Clinton-Obama foreign policy was a bust during her four years as secretary of state.

"It's going to come back to be, once again, an issue that I think really dogs her throughout the campaign."

Watch the exclusive "Fox News Sunday" interview above to hear Romney weigh in on the 2016 GOP field and President Obama's nuclear negotiations with Iran.

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