Betta Fish: Is this a male or female

Hello everyone I was sold this betta and they said it was a female and I have 4 other females and they are all in a 37 gallon tank and have been fine but this one is the biggest and most aggressive and keep flaring their gills I can see a black spot but not a white egg spot so I am unsure if it's male or female here are a few photos I'll try to add more later