you can go to the profile options and check the box that removes her posts from your wall. you won't see anything at all. But, if she wants to send you a message, she can.
Try it. I've done it with lots of facebook friends. I don't need to know every little detail about them. I use it to communicate with friends and family who also use it.
And, she won't know you've done it. You'll still show up as a friend on her list.