Is frequent bragging a sign of insecurity?

for example I know a girl and I know that deep down she is insecure but she puts on a confident act that comes off as fake.

you know, the type of girls who don't eat, won't go to the mailbox without a full face of makeup on, and talk about themselves and male attention too much.

also I notice that a lot of times girls who know they are hot don't feel the need to talk about it constantly or talk about how much male attention they get all the time, only the insecure girls do this stuff.
Is frequent bragging a sign of insecurity?
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