He didn't say that. He said that there's no way he can know beforehand because he doesn't trust the establishment.
e.g. Look at the Republican party primaries. He was asked if he lost would he support the candidate who won. It's a similar thing and he first said he wouldn't and then he did make the same pledge as the rest.
What we also have to remember is that it was the other GOP candidates who in the end didn't support him.
No what he says over and over again is that the election is rigged and did nothing last night to dispute that when asked.
A candidate for POTUS questioning the legitimacy of our democratic process is irresponsible and sets a very dangerous precedent. As I said it borders on criminal behavior.
He is repugnant and a danger to this country.