Tell him that it's forbidden where you came from ,for a woman to befriend a stranger ,that if you do the two of you will die,be serious when telling him this ,and make him feel that u would have love to befriend him if not this forbidden thing,
why i said this is cos i have seen where a thing like this happened if u tell him no just like that there will be problem but that is if you are in his country but if his in Ur country u ve got nothing to worry about,see yaaa!
thanks, it worked!!!