You don't have to guess, there are plenty of polls. He is historically unpopular.
http://www.realclearpolitics.com/epolls/other/president_trum...
http://www.realclearpolitics.com/epolls/other/president_obam...
"Trump will never make it past the first debate"
"Trump will never win the Republican primary"
"Trump will never win the general election"
(You are here)
(I'm over here)
"Trump will never do jail time."
"Trump will never lead a prison riot that gets a thousand prisoners killed."
"Trump will never cruise the nuclear wastelands of America with his gang of misfits in their hacked together deathmobiles..."
You mean the same polls that were 100% sure that he wouldn't win? [1]