Concerned about a buyer.

I just sold a graded card for 1300 and for some reason it isnt going through the authenticity system. The buyer shows they are located in Singapore which I paid the international fee for, they only have 3 purchases, each with positive reviews. The delivery address appears to be an international shipping company. I've reached out to the buyer to confirm all this and they responded "Hey there , thanks for checking in with me on that, But yes it'll be ship to the US to a friends place". I could see all this being above board, just wanted to get consensus on how others would proceed. My gut says not to ship.