The Question and Answer section for Arms and the Man is a great resource to ask questions, find answers, and discuss the novel.
She thinks the man behind the curtain looks and sounds like an Austrian,
No, you are one of the Austrians who set the Servians on to rob us of our national liberty, and who officer their army for them. We hate them!
The presence of the Serbian's revolver evokes fear in Raina, but it is unloaded, thus, not dangerous. I'm not sure what you mean about the "truth" about the revolver? Please add details.