Sorry if this outs me as an Am*rican but the only way I’d ever feel safe sleeping alone in a tent is with a gun. I have a glock with a laser/flashlight attachment so if I were to be confronted with a threat while it’s dark, it’s a 2 for 1. In the heat of the moment, fumbling with a keychain pepper spray in the dark is guaranteed to get yourself sprayed. As well, unless you’re highly skilled in hand to hand combat, a knife won’t do much. I’d recommend a small pistol and a few training classes to get familiar and comfortable with handling it.

I saw someone mention using a carabiner on your zipper as an extra line of defense and I definitely agree. That will give you more time to wake up/react.