Here's a breakdown of the pronunciation:
* "K" as in "kick"
* "H" as in "hair"
* "ai" as in "eye" or "high"
So, you would pronounce it "khair".
It's important to note that "khair" is a very general farewell and can be used in various situations. There are other ways to say goodbye in Pashto, but "khair" is the most widely used and understood.