the K1 is a fiancé visa. Same horror stories as all the ones in this thread. And to be fair the day she went most were denied. But they were doing tourist visas and were not married.
With a legit relationship and proper preparation you will be fine. I know married couples that were denied but in the end it was because they asked her a few questions she couldn’t answer.
Where are you going? She didn’t know.
Why are you doing a tourist visa and not permanent residency? She didn’t know.