The Saint's Magic Power is Omnipotent: The Other Saint (Manga) Vol. 1

Aira Misono is a run-of-the-mill high school girl, and never imagined that she'd be summoned to another world, let alone declared its savior. Yet from the moment the handsome Prince Kyle lays eyes on her, he's convinced that she's the long-awaited Holy Saint destined to banish darkness from his world. Aira herself maintains significant doubts. Is she really up to this challenge? She might be able to use magic, but is she really a Saint? Aira's fears and struggles only deepen when the woman summoned alongside her begins to look more and more like the one who truly deserves that title.