I have PocketBook 902 and it allows to select languages I have no clue what they are - one is very much Arabic looking, another one might be Georgian, and Hebrew is actually written in Latin letters "Hebrew", so for sure. And Russian too - they use hieroglyphs for letters, for example "zh": >|<
Besides, you can install your own fonts (so also your own Farsi fonts, if needed).
And it runs FBReader, and FBReader supports unicode.
So PocketBook is a pretty safe bet, besides, it supports lots of e-book formats as well.