The safe is necessary for two reasons. One: You protect yourself and your belongings (but please get a safe with a combination lock not just a key, our key was stolen and stuff taken even with that step!)
Two: It removes the doubt from any suspicions you have. Many times, I second guessed if I really had the money in my wallet or spent it, having the safe is something that also helps us not blame unecessarily.
Good luck!
TT