Immerhin faßte es der Fremde so auf, denn er sagte: »Wollen Sie nicht lieber hierbleiben?«

In any event the stranger took it as such, because he said, “Would it not be better for you to stay here?”

The German seems simply enough but since I am so lousy at it I am not sure how ambiguous the language itself is trying to be.  The context is certainly highly ambiguous.