I think girls like shiny things, so try to find them and show something shiny and expensive, they will fall on that 100 % sure.
Most of the girls/women don't get it.Even if you tell and show them that they can buy things with Bitcoin.
But this way it is just another payment option for them beside all other ones.
Girls are mostly not interested in new things as long as it hasn't reached mainstream or created kind of a trend.
The girl that you are talking about is not openminded in this kind of opportuinity, Obviously that girl is closeminded person. But
those kind of a girl showing not interest in bitcoin must take her understanding first anyway.