Transcript for Hillary Clinton Says She's 'Sorry'
As America goes back to work, back to school, for Hillary Clinton, it is back to a new reality. Her poll Numbers sinking fast. And tonight, she is talking exclusively with us. Saying I'm sorry, and not just once. Tonight here, no question off-limits. The private server. What was she thinking? Can she survive this? And the new headline tonight that at least two e-mails reviewed are top secret. And in a very candid moment, we ask, does she ever quietly wonder, why go through all of this again? We want you to watch and weigh in on Twitter and Facebook. And we begin here with her e-mails. Secretary Clinton, thank you. Thank you, David. When voters were asked, what is the first word that comes to mind when you think of Hillary Clinton, words like liar, dishonest, untrustworthy were at the top of the list. Does this tell you that your original explanation about the private server, that you did it to carry one phone, out of convenience, that this didn't sit well with the American people? Well, David, obviously I don't likeng that. I am confident by the end of this campaign, people will know they can trust me and that I will be on their side and will fight for them and their families. But I do think I could have and should have done a better job answering questions earlier. I really didn't, perhaps appreciate the need to do that. What I had done was allowed. It was above board. But in you sit here, milli millions watching tonight, did you make a mistake? I did. I did. As I said, it was allowed and there was no hiding it, it was totally above board. Everybody in the government I communicated with, and that was a lot of people, knew I was using a personal e-mail. But I'm sorry that it has, you know, raised all of these questions. I do take responsibility for having made what is clearly not the best decision. You mentioned everybody in the government knew that you were using this private server. Did fellow members of the cabinet know? Did the president know? Everyone I e-mailed with and I'm not going to go into names, but I mae-mailed with people in the white house, of course across the state department, knew that I was e-mailing from a personal account. It appeared, you know, as my address. The intelligence community inspector general telling ABC today that two of the e-mails carry the classification of top secret. That both e-mails were classified when they were created and remain classified now. One was about drones. One was about North Korea's nuclear program. Does this mean that classified information passed through your private server? Well, there still is a dispute. The state department disputes that. I understand why different agencies have different views. And I respect that. It does not change the fact that I did not send or receive any information that was marked classified at the time. At the time marked classified. Let me ask you, for the rest of us, the average voter and average viewer out there. Right. Who might wonder, how can some of these e-mails be classified and labeled as top secret today -- what changed in them so significantly that you wouldn't have seen red flags even just a couple of years ago as secretary of state, that you of all people would have known. That's a very fair question, and I think there are a couple of answers. One, sometimes events do proceed in a way that maybe there's a case being brought against somebody, maybe even a terrorist, and all of a sudden everything is classified. But North Korea's nuclear program, wouldn't that will classified -- There's a lot of public information about their nuclear program. I don't know the specifics about the one that they are claiming is classified. Let's go bigger picture here for a moment. Because many who, quite frankly, wanted to support you, have not learned of this FBI investigation, have learned of the I.T. Guy that helped set up the server planning to plead the fifth and many who have said to themselves, Hillary Clinton, of all people, have been in the public eye for so long, that she should have known, and perhaps the more important question they're asking is, can Hillary Clinton survive this? Can you? Yes, of course I can. I, as you might guess, have been around awhile, and there have been lots of, you know, attacks and counterattacks and questions raised. And I can survive it, because I think I'm running to be president to do what the country needs done. And I believe the American people will respond to that. She makes it clear, this is not a criminal investigation. We then ask her about the other news of the day, Joe Biden. Voters chanting this weekend, run, Joe, run. Y you were on the same team, you would have breakfast with the vice president. Would he make a good president? Well, I like Joe Biden a lot. And I think retrospekt, certainly, as I look back at it now, even though it was allowed, I should have used two accounts, one for personal, one for-related e-mails. That was a mistake. I'm sorry about that. I take responsibility. And I'm trying to be as transparent as I possibly can to not only release 55,000 pages of my e-mails, turn over server, congress, something I've been asking for for nearly a year. But I did hear a word in there just a moment ago and I'm curious. Would you acknowledge that you make a mistake here? Because you wrote in your own memoir last year, just how important using the word mistake is in politics. Right. You wrote, in our political culture, saying you made a mistake is often taken as weakness when it can be a sign of strength and growth. And so,s the more vehement you are, that's leadership. Do you think Donald Trump is just a leader of rhetoric in speeches? Well, he won't tell you how he would do anything. Americans have watched you as first lady, they watched you run for senate, they watched you run for president the first time, you served as secretary of state. I want to know, in your most private of moments, is there ever an instance when you ask yourself, why am I doing this again? Yes, of course. Because it really is hard. And it's something that -- you know, just demands everything. Physically, emotionally, spiritually. It is just 24/7. I cherish and love this country. It gave me, you know, opportunities far beyond anything my mother or my father could have had. Is your mother's voice in your ear and give me one line that you repeat to yourself? You know, as you probably know, my mother had a terrible childhood. She was abandoned by her parents, she was rejected bill her grandparents. She was literally working as a house maid at the age of 14. And she told me every day, you've got to get up and fight for what you believe in, no matter how hard it is. And I think about her a lot. I miss her a lot. I wish she was here with me. And I remember that. And I don't want to just fight for me. I don't -- I mean, I can have a perfectly fine life not being president. I want to fight for all the people like mil mother who need somebody in their corner, and they need a leader who cares about them again. So -- that's what I'm going to try to do. Tomorrow, Hillary Clinton delivers a major speech on Iran, supporting the president and the nuclear deal with Iran. We had tough questions for her. What happens when the deal is done? Some predicting Iran would be just weeks away from a nuclear bomb. Her answer, tomorrow night, right here and much more tonight on "Nightline."
This transcript has been automatically generated and may not be 100% accurate.