If you set up an auction just for your buyer, who discovered that you have other items you did not advertise on eBay from some other source, but still want to pay eBay fees instead of sending her a Paypal Send Money request, I would suggest using her eBay name as the title.
Easier to find.
Rather than an auction set up a Good Til Cancelled Fixed Price listing. Give her a deadline. If she doesnt' pay within the deadline, add her to you Blocked list and change the title to something Searchable.