Verity Circle

• WWizards of the Coast2019-01-25
  Official Ruling
  If a creature enters the battlefield tapped, Verity Circle's first ability doesn't trigger.
• WWizards of the Coast2019-01-25
  Official Ruling
  For Verity Circle's first ability to trigger, the creature has to actually change from untapped to tapped. If an effect attempts to tap a tapped creature, but it was already tapped at the time, the ability won't trigger.
• WWizards of the Coast2019-01-25
  Official Ruling
  If a creature with vigilance is declared as an attacker and then becomes tapped while it's attacking, Verity Circle's first ability triggers.

Rulings via Scryfall