Wonder Woman’s Shield says that the quote OP gives is on the shield. However, The Badass Quote That’s Engraved On Wonder Woman’s Sword says that it is on her sword:
In the “Batman v Superman: Dawn of Justice: Tech Manual” (via Digital Spy), it’s revealed that director Zack Snyder wanted inscriptions on the sword and shield. After coming up with a “hybrid extinct language,” the team inscribed the sword with a quote from Joseph Campbell’s collection “Goddess: Mystery of the Feminine Divine.” Here’s the quote translated into English:
“Life is killing all the time and so the goddess kills herself in the sacrifice of her own animal.”
What is Written on Wonder Woman’s Shield in BATMAN V SUPERMAN? | Nerdist links to a transliteration of the inscription on the sword (it says shield, but the closeup of the sword has the same text), done by Vince Tomasso: The “Greek” on Wonder Woman’s Equipment in ‘Batman v. Superman: Dawn of Justice’
The Greek makes no sense, and it has random digammas and a letter that Tomasso did not recognise, and that I’m proud that I did: Sampi (in its arrow variant). It looks like they made up the language for the quote, and I would not be surprised if they just made up a bunch of random letters, rather than a fully-fledged language. But Greek it isn’t. The archaic letters do indicate this is supposed to be some sort of fictional pre-Greek…