The question where are you really from can turn an introduction into a refusal of the first answer.

The follow-up question rejects the answer given. Someone says where they are from, and the word really tells them that the answer was not the one being asked for, that their account of themselves has been overruled by a guess about their appearance. Usually there is no hostility in it, and the effect is the same.

If you are curious about someone’s background, wait until you know them and ask about family or upbringing rather than origin. Take the first answer as the answer. Curiosity is fine and the question of who gets to decide where someone is from is what makes that particular phrasing land badly.