Funnily enough, Sara and Sarah have completely different pronunciation in the UK, so I've never thought of that as a confusing one. Sara is pronouced like Zara, but with an S.
This is 99.9% true, with the exception of yours truly, because I am just that special.
Blame the parents: I never asked for this. Mum wanted 'Sarah'. Dad, for some bizarre reason, disliked the 'H' and wanted 'Sara'. Their brilliant compromise was a name 'spelt-Sara-but-pronounced-Sarah' (because that wouldn't result in their daughter spending a lifetime correcting people on spelling and pronunciation at all...).
Locally, both Sara & Sarah are assumed to be pronounced SAIR-ah if you speak English, ZAH-rah if you speak German (or your parents do), so it's a case-by-case basis.
There was a Sahra I knew once upon a time, and I assumed that it was someone's attempt to force the German (ZAH-rah) pronunciation. I found out after a few years of calling and asking for "Zahrah" that it was "SAIR-ah", because her mom thought that was how it was always spelled.
Oops. At least she thought it was funny.