In Dutch a V sounds like F and a W sounds like V. Same as in
German. So it'd be fie-EN or fa-EN.
Mum made it up and liked the sound of it. Her own name is
Monique and she always had other Moniques in the same class, so she liked the uniqueness. Gerdi and
Joanne are the young singer's mns, both after her grandmothers - so she's Vajen Gerdi
Joanne.
Oh, and because it's a made-up name, there doesn't seem to be any agreement on the spelling - some just copy the singer's version, others use what they think they've heard.