This site (in the submitted names section) refutes the theory of a Sanskrit origin for Sansa.
Not every ASOIAF name comes from medieval names. Some are derived from:
- Ancient names (Cersei /
Circe, Oberyn /
Auberon)
- more modern names (
Lyanna, Brienne)
- non-Western names (
Asha)
- made up names (Danaerys, Tyrion)
The name
Arya could presumably belong in the last three categories. Perhaps the fact that
Arya does not have a medieval-inspired name, like the rest of her family, is a deliberate choice to make her stand out more.
The only names I can think of that could be a direct inspiration for
Arya are
Ariadne /
Ariana,
Daria,
Maria,
Hilaria,
Berengaria. Or perhaps
Harry? (
Arya is called Arry when she's disgusted as a boy.) But I find it more likely that her name was created by GRRM to make her a more distinctive character.