Update: It turns out that even Russia's president Vladimir Putin himself quoted Bismarck as saying that phrase! (Source1, Source2).
It thus seems unlikely to be a made-up quotation, because it is unthinkable that the Russian president will use made-up quotations. I am very much curious to find the original German phrase and its context and spent a few more hours searching, but found nothing. That's a real mystery…
Reading an article for my Russian classes, I saw a quotation from Otto von Bismarck:
Но еще Отто фон Бисмарк сказал: "Меня не интересуют их намерения, меня интересуют их возможности". (Source)
The quotation as it stands in Russian is so ruthless, cynical, and thought-stimulating that I got really curious what Bismarck actually said in German and whether he said anything like that at all.
Let me translate the above Russian sentence to English and German as precisely as I can:
But already Otto von Bismarck said, "I am not interested to know their intentions. I am interested to know their capabilities."
Aber schon Otto von Bismarck hat gesagt: "Mich interessieren ihre Absichten nicht. Mich interessieren ihre Möglichkeiten."
Trying to find the German original, I made a lot of search requests in Google by combining the surname Bismarck with various German words and expressions that might be constituents of the original phrase, but found no trace whatsoever.
Trying to find a trace from the Russian end, I googled the above Russian phrase attributed to Bismarck and found hundreds of Russian websites quoting it as Bismarck's phrase, but was unable to find the German original or any trace to it.
My attempts to find an English or Japanese version have also been fruitless.
In Russian articles, the quotation is often used to support the idea that it does not matter what is or seems to be on people's minds. The supported idea is that what really matters is the actual balance of power. I even saw rephrasings with indirect speech like, "Bismarck said that capabilities give rise to intentions."
It does not seem very likely to be a made-up quotation, as there are quite a few hits in Google Books and even a hit in minutes of the Russian Parliament. Moreover, the idea expressed in the quotation resonates well with Bismarck's views as I can see in this history article.
The quotation might be, however, somewhat altered, as I saw a somewhat different version in an article by a popular Russian analyst. He quotes, in Russian, Bismarck as saying, "What matters in politics is capabilities, not intentions. Intentions change, capabilities remain."
I humbly hope that history fans and experts of this SE could help me resolve the mystery.
My question is this: Exactly what did Bismarck actually say in German? I would also like to know the context in which he said that phrase.