How to Spot a Fake??

Alright, so I have booked my first four nights in Ipanema. I thought I had booked this homestay, but I need to wire them money today and I'm a little nervous. It's a lot of money to send (relatively speaking) and the deal seems too good to be true.  So I'm wondering if it might be. 

If it was a credit card on a secure site, it'd be one thing... but this is a wire. How do you spot a fake?

I haven't really gotten burned when making reservations before, but I know people that have when going to S. America (big time - like their program didn't even exist) so I'm skeptical about this one...   I think I'll call the lady and see if she answers. Hmm.