Can you tell if someone KNOWS they're attractive?

In the opposite sex or in general, can you usually tell if someone already knows they are attractive or really good-looking? If so, how can you tell? Do they have a cocky disposition or a vibe about them? Do you think that most obviously attractive people know they are attractive?

And if they do know they are hot or attractive, does it affect your opinion of them or if you would want to date them?

Updates
11 mo
And is it a red flag if somebody knows they are attractive?
Can you tell if someone KNOWS they're attractive?
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