How do I know if seller is selling genuine cables?

Having a legit receipt helps but the seller could have just purchased one legit pair & is still passing off fakes. Places like Audiogon are alot more reliable then places such as Ebay (where your more often to get a fake vs a real most of the time) but when looking though Audioquest cables on here, I have seen a suspecious seller even on here (prices seem to good, from Hong Kong).

Origional packaging would be a plus as some fakes won't include this & in the past if they did, it was usually poorly executed. I see the guys copying Audioquest have got much better with their fakes, their packaging now looks very close to the origional. As mentioned some companies will verify the cable for you (some to send in the cable while other can be done via emailed pics)

Agree that the only way to be sure is to have the cables verified by the manufacturer. I once bought a pair of Audience Au-24 i/cs that looked to be genuine. When I went to re-sell, Audience contacted me because mine appeared to be very similar to counterfeit cables that they had seen before. I had a lengthy and pleasant email exchange w John MacDonald, the owner and ultimately he offered to verify them at no charge. So I guess the answer is to buy from a reputable seller w the understanding that you have the right to return if the manufacturer says they are not genuine.

Listen to 'em if they sound right LOL!

Fake cables might sound good too, that doesn't mean that you want them.
You could buy from me if I had anything to sell. I don't at the moment. That would be a guarantee. My cables are not fakes unless they are made so well that even the manufacturer missed it.

Only buy from persons with many killer feedback then pray.