Breakdown of Он оказался хорошим человеком.
он
he / it (for a masculine noun) / it (for a neuter noun)
человек
person
хороший
good
оказаться
to turn out to be (perfective)
Questions & Answers about Он оказался хорошим человеком.
Why is it "хорошим человеком" instead of "хороший человек"?
The verb оказаться (to turn out to be) requires the noun or adjective describing the subject to be in the instrumental case. Therefore, the nominative хороший человек changes to the instrumental хорошим человеком.
Is "оказался" related to the verb "казаться" (to seem)?
Yes! They share the same root, and both verbs require the instrumental case for the description that follows them. While Он казался хорошим человеком means "He seemed like a good man," adding the prefix in Он оказался... shifts the meaning to "He turned out to be" one.
If we were talking about a woman, would "хорошим человеком" change to feminine?
No, it would stay exactly the same. The noun человек (person/human) is grammatically masculine. Even if you say "She turned out to be a good person" (Она оказалась хорошим человеком), the phrase remains masculine instrumental to match the word человек.
Since this lesson is about "удаться" (to succeed / turn out well), why can't we use it here?
While both verbs can translate as "turn out" in English, they are used differently in Russian. Удаться is for actions you successfully manage to do, requiring the dative case plus an infinitive (like Ему удалось...). Our sentence is about someone's identity being revealed, not an action they accomplished, so we must use оказаться.