This doesn't feel particularly white. It should also say "dealt damage this turn"

It's flavorfully derived from cards like Shining Shoal and Divine Deflection. Admittedly, the flavorful idea is that the creature enchanted killed the other creature by blocking it. The creature being killed when the enchanted creature is attacking is out of color. I can remedy this by either making the card red and white or changing it to "Whenever a creature dealt damage by the enchanted creature dies during an opponent's turn," which means the enchanted creature wasn't attacking at least (of course, there's other cards that could spice that, but that's getting into fringe stuff that'd only come up in casual formats [additionally, I only envision this as a stand alone collection of cards, with the original cards not intended for play with cards outside of the set]).