Tactfully tell her there are other things in the book that you want to make so You can't loan it. Then give her the title, author's name, and ISBN and tell her to go to her local library and borrow a copy there. I would do the same with a pattern telling her you may want to use it again and want to keep it handy. Give her the info needed to order her own copy. I have been burned by loaning things and I do not do it any more, except for my daughters.