I must admit I do not lend out books anymore because of this very reason.

My books are very precious to me, but they are mine, and not for you to hand around like my study is a library! lol
Too many do not come back and it ticks me off - they are expensive, some of them sentimental and others just plain hard to get.

Anyway, I would call and tell her you want it back, so get it back or replace it - simple - none of this "see if I can get it back" rubbish!