Hello, nice to meet you.

I'm from S. Korea.

I'm teaching in Elementary school.

(I'm teaching at an elementary school.) Using "at" sounds more natural.

Sometimes my students tell me 'English is difficult' & 'I hate English study'

(Sometimes my students tell me, "English is difficult," and "I hate studying English.") When writing, "&" is not usually used.

So I want to help them, I want to speak english well.

(So in order to help them, I want to speak English well.)

My job is teaching, so i can help the korean learners well, I think:D

(My job is teaching, so I think I can help Korean learners very/pretty/especially well. :D) In this context is sounds more natural to use a descriptive word before "well".

Nice job! I hope these corrections are helpful to you and that your students will be able to persevere through studying English! :)