Definitely [name_f]Sarah[/name_f]. I pronounce [name_f]Sara[/name_f] as rhyming with [name_f]Zara[/name_f].
[name_f]Sarah[/name_f] is the more popular spelling, but [name_f]Sara[/name_f] is not uncommon at all. I feel like it would all be a matter of personal preference as to which you prefer. Either way she would get her name spelled incorrectly once in a while but as someone else said, “[name_f]Sara[/name_f]/h with/without an h” isn’t a hard thing to say.
As for the pronunciation re. [name_f]Sara[/name_f]… I have never heard of [name_f]Sara[/name_f] pronounced Sahr-uh in the United States… maybe if you’re in Europe (which you might be)… but yeah, never in 22 years have I heard someone pronounce that name differently than [name_f]Sarah[/name_f].
[name_f]Sarah[/name_f], for sure.
Interesting! I’ve never heard [name_f]Sara[/name_f] pronounced the same as [name_f]Sarah[/name_f] - seems like it might be a US only thing? https://en.wiktionary.org/wiki/Sara
Everywhere else seems to have it rhyme with [name_f]Zara[/name_f] (first syllable like “car”) though according to wiktionary the UK does have ‘[name_f]Sarah[/name_f]’ pronunciation, and one that’s more like “[name_m]Say[/name_m]-ra” if I’m reading it right? I’m NZ, and I’ve got 9 years on you 
I’ve got 9 years on you and have never heard [name_f]Sara[/name_f] pronounced the same as [name_f]Sarah[/name_f]! But like you say, it might be a US thing. wiktionary seems to suggest most other countries pronounce the first syllable of [name_f]Sara[/name_f] like ‘car’, with the US and sometimes UK being the exceptions. I’m NZ for what it’s worth.