She really looks like a mix to me.
If she is purebred - you should be able to track down her AKC registration. If they have her registered with another organization - forget it - it's likely not right.
With AKC - you can track the lineage - way back. Not for free, of course, but what is free these days?
I have raised and bred Saints for a number of years now and currently have two that are registered. One is not show quality, but of good stock, and her pups go for $600 limited and sometimes twice that for full registration. The other one is still a pup - about 4 months - but she is show quality - lineage is from champions, and she was $2300. There is quite a price gap between your pup and most purebreds, although you can buy Saints for around $500 on some bulletin boards. Just be careful.
If you don't need a purebred - those photos show what looks like a very nice dog, but kind of high priced for a mix.
But - I have to say that there are a great number of Saints that have been poorly bred - sometimes a breeder registers a litter where more than one sire got to the bitch. It's against the rules - but some are just not playing by those rules. And it hurts everyone.
If you can wait - our dam was just bred to a sire from good lines and should whelp around Oct 4. Our pups have been placed all over the nation - some in CA, others in NY, VT, among other states,and even one in Canada. We don't ship until they are 8 weeks old, and only on Continental because they control the temp in their cargo for pets.
But, I'm not trying to sell you a pup. Just letting you know. You may end up with the sweetest dog - one that you will love forever with the girl you are now looking at. There is so much more to owning a Saint - or a Saint-mix, than just being a purebred. I also have a couple of 'mutts' and I wouldn't trade them for the world.
Good luck with your decision.