I tend to pronounce both the same, as they are the same name. There are plenty of Hebrew names that can have the H on the end or not, and the pronunciation doesn't change. Kezia and Debora are pronounced no differently (at least they shouldn't be), if spelt Keziah and Deborah, for example.
However for some reason, here in the UK (and I think also in Ireland) Sara has tended to be pronounced SAH-rah, as opposed to SAIR-ah, although I do also know women called Sara here who pronounce it SAIR-ah.
As I said, my instinct is also also go with the SAIR-ah pronunciation, unless corrected.
I love the name, I think it's classically beautiful, and I don't understand the hatred some have towards it. It's no more bland/dull than Emma, which is still hugely popular, so I don't understand why Sarah (this is my preferred spelling) has fallen out of favour, while Emma hasn't. I would pick Sarah over Emma, every single time, although I have nothing against the latter name!
~Charley~
https://www.behindthename.com/pnl/184785
It is a Yorkshire habit to say what you think with blunt frankness~Frances Hodgson Burnett, The Secret Garden~