Trump is an unreliable and untrustworthy person. He knew that jebbush.com was directing people to his own site because he posted about it via his Twitter account. Trump said in a tweet that he bought the website after Jeb Bush forgot to renew his domain rights and it has now turned into a publicity stunt.
There is research by Politico backing up the fact that it wasn't Trump. Search it up on the internet and it wasn't even his real twitter witht he post. There is no evidence that he knew about the website and those that disagree just hate the fact he's doing well.
A site with the domain name JebBush.com redirects to the real estate mogul’s official presidential campaign page, donaldjtrump.com, and features Trump’s slogan with options to support or donate to his campaign.Trump would definitely have been aware of the fact that the website jebbush.com was directing people to his own site.
Donald Trump is the master of public relations, and he lives by doing things like buying the jebbush.com domain name. He definitely knew that jebbush.com was directing people to Trump's site. He even tweeted about it and made it a bigger deal than it is. This is the kind of game he likes to play.
There's no doubt in my mind that, as narcissistic as he is, Donald Trump knew that jebbush.com was redirecting people to his own site. In fact, I'm convinced that he was closely involved in making sure that it happened. If he was directly responsible, I'm sure that he at least had knowledge of it ahead of time.