[yodsanklai]

Seems you're not eligible to a Visa Waiver if you traveled to Iran or Sudan. Which means you need to apply for a visa at your US embassy [1] (which in my case was expensive and required a one day trip). Also it's not only a matter of having an Iranian stamp on your passport. You're not eligible for the VWP even if you visited this countries. I wouldn't try to lie about this!

"When can’t I use the VWP (ESTA) and need a visa?

Due to personal circumstances:

you traveled to certain countries (Iran, Iraq, Sudan, Syria, Libya, Somalia, and Yemen on or after March 1, 2011)"

[1] https://nl.usembassy.gov/visas/visa-waiver-program/