Ann, if I am reading your question correctly, you are saying that your mother's LNAB (Last Name At Birth) is Beste but should be Sage. If that is the case then you need to edit her profile and click the link to change her LNAB and enter Sage as the new value. Make sure that you have Beste in the Current Last Name field if that is the last surname she was known by.
EDITED TO ADD:
I just looked at her profile and see that her LNAB is - correctly - Sage and her Current Last Name is - also correctly - Beste. You also made Beste her first name and put it in Other Last Names field, which are not correct. You need to put Mary in both Formal First Name and Preferred First Name and Ellen in Middle Name. You can make Other Last Names blank. That should fix everything up nicely.