How do you spell faith in Russian?

If you mean the name Faith, it's a tough one, because Russian does not have a sound or a letter for th. It would have to be Фейт, which, when read back, would sound like Fate, not Faith. Sorry!

Another way to spell it is Фэйт. There is almost no difference to how a Russia would read one or the other. Pick the one that looks prettier to you.