"The reason for my participation in the competition of Korean language is my desire and the hope that my work will be interesting and useful to the audience (public)."?
한국어 경연 대회에 참가하는 이유는 저의 "일"이 관객들에게 도움이 됐으면 하는 소망과 바람이 있기 때문입니다.
i translate "work" into "일" because 일 is commonly meaning among many meaning of work.
of course, it's possible but i think it is a little unclear and unnatural.
so please let me know which meaning you want to express by writing another word
then i will recommend fit word in that situation.