What is the best way for to ask my friend to pay a debt?

We agreed nearly a year ago for me to rent some small household items when we first moved in. I got the bill at that time and kinda figured that she would remember and ask me the amount but she never did. I figured with the hussle and bussle of moving in I would defer it to another time thinking she would remember about the bill since the rented items are used everday. It has been about 9 months now (yeah kinda put it off and forgot) and she still hasn't offered and I still haven't asked. However, the bill was quite large and I need the money. So what is the best way to ask her to pay what she owes?