YOU SAID:

I dont think i should have to go to karate when i dont want to because its not beneficial

INTO JAPANESE

私はしたくないときに空手に行かなければならないと思う

BACK INTO ENGLISH

I think i have to go karate when i don't want to

INTO JAPANESE

私はしたくないときに空手に行かなければならないと思います

BACK INTO ENGLISH

I think i have to go karate when i don't want to