That question is fucked. If it's someone you've never met then safety isn't guaranteed.

I've had several gf's who've been into "rape". You see it in their eyes if you're doing it right. Hornier=good, anything else = bad.

I would never do a rape scene with someone I didn't know well. For one, I could potentially get arrested afterwords. Some girls are C-R-A-Z-Y. I almost was once but that was a way more complicated situation than just the sex and involving her boyfriend.

How do you define authentic? The girl not taking pleasure? Any consensual sex needs both parties to get something from the sex. I think you need to do more thinking on what exactly it is you want.