sure.
that depends what you consider to be credible
you have posted instances where the same quote is claimed to exist. None of them claims to have a source for it, just echoing that someone else on line has posted the same quote. If I created 7 websites, I could have 7 sites that all say "the quote has no source" but all seven would have the exact same basis -- that is, nothing. So just posting instances where a claim is made is categorically different from providing an actual source.
In the quora page which I linked to, there are more than 6 individuals attesting to its being false after researching and trying to find a source. Why are those six (and more) less reliable than the people who did no research but just copied and pasted the supposed quote?
that links to a search page, nothing more.
who are these people and why do you believe that they have sources for their claims?
that's just a site to which someone added the same, unsourced quote.
yeah...um
not found on that page
So bottom line, nothing that provides any evidence that the quote has a foundation in reality.
Does it offend you that a foreign politician sees that American policy is maleable? Wow.