You should NOT pay that much for Tahitian pearls- especially the quality she is selling. I saw Elle Florence's website and she sells an "image" for sure, but the quality is the same as many sellers on Etsy. Please support them as I know that many get their pearls from the exact same source but charge in the $100s at the most...and not $700s (red flag there - this is a very steep markup for the same stuff). Look at some of the Hawaii-based sellers on Etsy. I can't show specifics but a simple search should help. I know this lady has a business to run, but the prices she charges over what the wholesale price is for Tahitian pearls from the same sources is bat-sh*t crazy. Anyone can go on vacation to Tahiti, take photos, and claim all their pearls are "authentic" but I know you will be safe to get high quality designs from other sellers who don't charge that crazy markup!! Yes, the high end (think Mikimoto) get atmospheric in prices, but for your everyday wear pearls like she is selling you could get a much better deal.
Side note, I saw more red flags on this seller when I did a Google search and although a popular gossip site came up, there is a lot of shadiness going on. Buyer beware. Good luck on your search.
Interesting -- I would not expect to get genuine Tahitian pearls at all for $700 for a strand of round pearls... that seems extremely cheap to me? And generally I've found that you get what you pay for. A lot of people like Pearl Paradise for good prices on the internet. TBH I think I would choose to buy online rather than at most retailers these days. You just have to know where to look.