YOU SAID:

i have to think about it

INTO JAPANESE

私はそれについて考えなければなりません

BACK INTO ENGLISH

I must think about it

INTO JAPANESE

私はそれについて考える必要があります

BACK INTO ENGLISH

I need to think about it

INTO JAPANESE

私はそれについて考える必要があります

BACK INTO ENGLISH

I need to think about it