None of what you say is "ultra left" by the way. Merely left of centre.

If you hold far-right views, even centre-right will look ultra-left to you, and you'll see yourself as centrist when you look at the ultra-right.

In as much as i dislike a two party system, i still believe @Servant et al got it wrong and it it not a matter of forced overlapping. In other words Trump is genuinely the face of majority of the republican supporters and US politics is now more extremely polarized... majority of republicans supporters are now extremists.

I'd say the majority of them are far-right. However, it's polarized to the point where most democrat supporters are far left as well.

So why are more intelligent, more moderate, more politically experienced, more reasonable candidates such as Jeb Bush in single digits in the polls?

I can only speak for myself, but I think many feel the same way where we absolutely don't want any more dynasty presidents. I'd vote for either Trump or Sanders before any more Bushes/Clintons.

If you hold far-right views, even centre-right will look ultra-left to you, and you'll see yourself as centrist when you look at the ultra-right.

Absolutely. It's different for every region as well. For example, our most left-wing candidates might seem right wing in Scandanavian countries.

For the one reason: The two party system is partially compensated for by the multi-candidates with policies from extreme conservatism to moderate conservatism during the primaries.... So why are more intelligent, more moderate, more politically experienced, more reasonable candidates such as Jeb Bush in single digits in the polls?

He has said some dumb things. All the candidates say dumb things just people have focused on his for whatever reason. Probably having a father and brother as president and the chad thing.

I think people like Trump because he isn't afraid to say what he thinks and isn't all wishywashy in this stances. All the other candidates don't generally make any firm statements on things one way or another so they don't upset people. President should make the best decision for the people, not worry about making everybody happy. I don't think Trump should be president but we certainly need somebody who isn't a limp wrist like the current president and candidates. I can only assume that other people are starting to feel the same way. But probably more likely people are only interested because of the show he is putting on right now.

(long rant)

Do you know all of this to be the truth, or are you a victim of manipulation and misinformation as well?

Impossible to tell, but 99% of this is stuff that has been in the news on public TV, or in the press. Of course that implies that it's necessarily not the complete truth since media are generally not telling the truth, ever.
But if they are biased, they're rather biased towards playing everything down. Such as with the crime statistics where they presented very clear numbers that show a per capita rate which is 8 times as high as average, and then saying "but that is normal, nothing to worry about".

To name two examples of verifiable events, it was the major of Salzgitter (Klingenbiel) who brought up the debate on compulsatory expropriation on private people in a NRD interview, and Berlin is to my knowledge already doing it with hotels (according to a report that I saw, the owners were reluctant to rent rooms to the city because the vouchers that they get are kind of worthless, allegedly it takes 3-6 months until they're being paid, if at all). The story about the mass brawl over the Qaran refers to the event in Suhl on August 2 (was on public TV and in the papers as well).

Considering the rant about ISIS hiding amongst immigrants/refugees, and the tone in general, I think some element of bias can be assumed

Not so, this particular thing is something that was being said verbatim on ARD a few days ago by some polictician (bavarian state ministery if I remember right, but might as well have been CSU leadership, I would have to lie... don't remember). Anyway, what he said was that as it's going now, he is very concerned because they have absolutely no control of who enters and they have no idea how many ISIS terrorists are among them, and it's a huge concern for inner security.

But, my point is, there is nothing wrong with helping people who are in need, or with immigrants.

However, you can do everything in different ways, and the way our government is doing it is the most shitty way possible. It's a straight course into desaster.
You can't even blame the clandestines for that. I mean, they take what they can, they'd be stupid if they didn't...

But here, we're finally back on topic again... what I was actually saying in my first post (before I was seduced into that rant) is that Trump isn't necessarily all that bad. Sure, he has no manners, his haircut is, well... let's ignore that one, and his ideas (like that big wall to Mexico) sound kind of moronic, but I assume that nobody really takes these ideas literally!
I'm strongly inclined to believe, and unless you think that he is really insane you should believe that too, that this wall is merely a figure of speech.

Which basically means no more and no less that Trump goes the "strictly pro US" route. Which (for the US americans) is not a bad thing. Of course it will be bad for the others, but for the US americans, it will be good.

(long rant)

Do you know all of this to be the truth, or are you a victim of manipulation and misinformation as well?

Impossible to tell, but 99% of this is stuff that has been in the news on public TV, or in the press. Of course that implies that it's necessarily not the complete truth since media are generally not telling the truth, ever.
But if they are biased, they're rather biased towards playing everything down.

Wait, the press? Biased towards "playing things down", ie. away from sensationalism? Your press must be very different from ours here in North America. :P

The leadership of the CSU, which is a local Bavarian party (sister-party of Merkels CDU but more to the right), regularly proclaims they are going to pursue some stupid thing. Although they are part of German government they always play the squeeky wheel, to ensure they are not forgotten (they need like 50% in Bavaria to get over the 5% hurdle for getting into German parliament, as they only put up candidates there).

The press knows they only do this to gain publicity and does not want to look stupid.

By the way, I hope to see the dissolution of NATO before I die..