YOU SAID:

i could care less about this thing

INTO JAPANESE

私はこのことについてはあまり気にしないだろう

BACK INTO ENGLISH

I would not care less about this

INTO JAPANESE

私はこれについてあまり気にしないだろう

BACK INTO ENGLISH

I do not care much about this

INTO JAPANESE

私はこれについてはあまり気にしない

BACK INTO ENGLISH

I do not care much about this