Josuke and Okuyasu just saw you defeat an enemy Stand user in a yoctosecond which made them impressed. What made it even more impressing for them was that you look like a very feminine and beautiful lady. You were a demoness and they could see that. You had grey hair, blue to black horns, long black catlike tail, pale skin, grey eyes, but other than those features they noticed about you, they liked you either way and found your features pretty cool. Only added to your beauty.