Legal Question in International Law in Kentucky

The real answer? You won't. Not unless he has assets in the US. Also, you'll spend more money on suing him than you are probably getting sued for. Service itself is expensive. For instance, in Canada under the Hague Convention, the complaint has to be translated into French, because it has to be served in both of Canada's official languages. I'd say if we aren't talking about a significant amount of money, cut your losses and remember the rule I myself have learned the hard way from solo practice: CASH UP FRONT. Promises are meaningless, even from "friends."