Adding Death Knell to my Wizards spell list.

[-Markus-]

Hi,

I have a lv 12 Wizard/Rogue, with a CL of 10.

Is there a way through feat or magic item, to add Death Knell to my spell list?
I am aware I can use scrolls or wands, but I prefer something a little more permanent.

We use the rules RAW.

Edit:
Figured it out. I can use the faith magic arcane discovery.