Similar thoughts as others, I thought Anais ( French ) though she could have used Ami or Amie or alternatives
As Galium said, Annis is variant of Agnes
'My book' gives Annus, Annis, Annice, Annes, Anise, Anis, Anesse as variations of Anice ( English ) an alternate form of Agnes
also Annus a variation of Anci (Hungarian ) a form of Hannah