(
Saibh,
Sadb,
Sadbh,
Sadhbh,
Sive or
Sabia)
It's SAH-eev, but I don't like this eccentrically exhausting and arduous spelling, the same goes for
Saoirse,
Siobhan & Siun.
Personally, I always prefer the simplest variant, namely
Sive resp. Seersha , Shevonne & Shoon or even better the more attractive alternative
Sabia (Saah-bee-aah).