The Witch Craft Works (ESub).

  Takamiya Honoka is a regular student whose only problem seems to be that he sits next to Kagari Ayaka, the school's #1 beauty. They have never spoken to each other before and any small interaction between them immediately results in her fanclub beating him. Yet when a falling part of the school's building is about to send him to the afterlife, it's Kagari that comes to his rescue. Only... she's dressed as a witch, carrying him in her arms and floating on a broom?! Kagari tells him it is her mission to protect him and that now she can finally protect him openly rather than undercover.