A "10" in Thailand will most likely be a lady from the upper echelons of society, and from a wealthy family. She will be well-educated at the best schools and likely went to one of the better universities, or perhaps even was educated abroad. She will have very fair skin, and soft features. She will be refined, extremely classy and probably have expensive taste as she has likely become accustomed to men fawning over her and putting their very best foot forward. And some of those will be very wealthy men. As a rule, foreigners don't date these Thai women.
The best most farangs get is about an 8 - and even that is the really high-achieving foreigners.