DavidK gave the right answer. They have different meanings. "You really are beautiful" could be used when someone is surprised by your beauty, or when one is emphasizing that it is true that you are beautiful. "You are really beautiful" just means that you are very beautiful.

Both are correct, but they have different meanings. English is full of wonderful subtleties! You are really beautiful. (‘Really’ is just an intensifier. It means ‘You are very beautiful’) You really are beautiful. (Here ‘really’ confirms that the statement is true. It’s real, not pretend) An example: A to B: You’re beautiful. B to A: You’re just saying that to make me feel better. I’ve never been good-looking. A to B. No, I’m not. You really are beautiful. The ‘really’ here is to emphasize the truth of the statement.

DavidK gave an excellent answer.

same meaning

They are not similar. You are really beautiful ( is correct)