The fact that people are claiming that it sounds at all like he said "I'd probably have a very good relationship" is laughable. Even in the WH audio, which is muffled, there's no sound between I and probably.
If you want to argue that what he meant was "I'd", have at it. But he pretty clearly doesn't say it.
Anyways, here's the next bit of the transcript.
"I probably have a very good relationship with Kim Jong Un of North Korea. I have relationships with people, I think you people are surprised.
WSJ: Just to be clear, you haven’t spoken to the North Korean leader, I mean when you say a relationship with Korea—
Mr. Trump: I don’t want to comment on it—I don’t want to comment, I’m not saying I have or I haven’t. But I just don’t—"
He's consistently talking in the present and not about hypotheticals. It's completely reasonable to argue that he meant something else and misspoke.
But stop pretending he said "I'd"