I'm sure. But if Hillary is his opponent, there will be a lot of trash and mud that can be dredged up and thrown at her too. Trump can fall back on his standard explanation that he was just talking off the top of his head, not playing by a script. Hillary has to explain her entire prior record. If Sanders ran against Trump, he would probably win.
Sanders is the only one Trump would beat. Hillary will run at least the most effective negative ad campaign against Trump since LBJ did with Goldwater. I have explained this in other threads, but here is how it will go:
All this violence at Trump rallies will amount to the most effective negative ads in the general since LBJ's against Goldwater. Either the Hillary campaign or some PACs will show Trump more or less egging them on as he has in in past rallies, then follow up with clips of minorities being pushed, shoved, and punched by the crowd in his rallies. Mark my words, that is exactly what they will do. They will mix those ads up with others where he says some of the most outrageous things he has said and then others showing where hate groups like the Klan endorsed him. Not only that, but they will tar every Republican running for reelection with the same Trump hatemongering.
Not only will it further destroy him with the minority vote, but it will also curb his ability to bring in working class white Democrats as it will shame them into not voting for him (just like with Goldwater).
They will take it even further though, as they will run all the bigoted statements he has made in regards to immigrants, particularly Hispanic immigrants, and even further destroy him with the Hispanic vote. A Republican needs at least 40% of the Hispanic vote to win in November. The last Republican to do that was Bush in 2004. Trump does not stand a chance in hell of getting even half that. Hispanics look at him like Blacks did George Wallace. The only Hispanics he will win are the few that are in the Republican Party.
Hillary is a flawed candidate and Bernie is unelectable in the general. With a candidate like Kasich, the Republicans would probably win in November, but they are going to absolutely get their ass kicked with a candidate like Trump or Cruz.
The only reason why the Republicans Trump is running against have not done this is they are trying to appeal to the same bigots that are in Trump's base, a Democrat will care less about that, but rather will want to make sure that those bigots are all that he has voting for him come November. The Republican establishment knows this and that is why they are scared to death of him being their candidate.