Girlfriend for rent? Yeah nah! it screams desperate and needy...though I'm sure a few blokes here could do with the service.

Otherwise, a good idea if you can pull it off, quit your day job and make a living from it.

My only suggestions for your entrepreneurial initiative:
- introduce smexy's into the portfolio (ie nobody wants to pay for a fucken starfish date)
- introduce travel companions (there was a thread on the topic)
- introduce threesome dating

There's a similar service in the US (perhaps get some pointers from their setup
https://gfrental.com/

Good luck!