If you haven't been together long enough, under enough circumstances, for her to get it, we won't be able to tell her.

It took several years before my wife/other understood not merely the utility, but the necessity of carrying a knife at all times.

Interestingly, after Katrina, she no longer questions my knife/light/gun by the bed obsession/compulsion.

I guess I come by mine honestly, though. I grew up on a ranch, where a knife is litterlaly more important than your pants. And, both my father and uncle were in the pacific in WWII. My dad was on nasty little islands where they slept with a .45 and a knife under their pillows, when they had pillows. The knife was to cut yourself out of the tent. My uncle was exec on an av-gas tanker, and a knife was considered to be an essential extrication tool.

I am remided of the cliche, "why ask why?"