I also suggest you ask yourself why you don't want to lend to a friend at all. Is she not really such a good friend? Have you had experiences which make you think your items won't be returned or well taken care of?
I agree with Shakespeare's "Neither a borrower nor a lender be," but occasionally I do borrow and sometimes I do lend. It's not too bad to help a friend when she needs something - a few eggs, or a lawn tool for a few hours, or a book I've told her about. If it's my car, that's something else, unless it were an emergency (but I might drive her someplace if I could). If it's money, that's a whole different category which must be talked about by itself.
Occasionally I am sorry I did the lending, but I would usually be sorrier if I hadn't extended the help and taken the chance.
At any rate, subtle hints aren't working for you. If you're really set on this, you just need to say no out loud: "Sorry, Olive, but I make it a principle that I don't borrow and I don't lend - ever."