Of course, Iran is safe, Iran is one of the safest countries in the Middle East & in the world. If you have never traveled to Iran, I suggest you to visit Iran (Persia).
Despite the sanctions against Iran, you can safely travel to Iran, make online payments, and remember sweet memories of Iran for years.
You can easily and safely make online payments in Rials, Dollars and Euros.
Of course, all nationalities can travel to Iran without restrictions. The visa process is 3-5 working days for all nationalities and 30-45 working days for American, British and Canadian nationalities.
