Hello everyone! I'm a new forum member who is learning to speak both Japanese and Korean. Most of my effort is going into Korean; I put my learning of Japanese on hold recently. Someday, I would like to teach English abroad. It's really nice to meet you all!
The Korean writing system is the easiest of the three writing systems. There is no need to memorize ideograms; the system is simple and can be learned very quickly. As far as pronunciation goes, I would say Japanese is the easiest. If you're worried about grammar, Japanese and Korean are nearly identical. I can't speak for Chinese in that regard.