She doesnt "sell herself", she is not doing compensation dating (that also doesnt necessary mean sexual favors) and Girlfriend Renting is a service in the US of A that also explicit states they are NOT escorts, plus family rental services do exist in Japan to be stand-ins for social events (such as weddings) or other reasons (suck as friends for Hikikomori as a attempt for then to break their isolation).
As I was looking for this, I found men in China are using a app to rent a girlfriend to take home for Lunar New Year in an effort to please their parents so yes, this is kinda being a bit on the realism side.