YOU SAID:

I bet this sentence remains the same

INTO JAPANESE

私はこの文章が同じままであるに違いない

BACK INTO ENGLISH

I must keep this sentence the same

INTO JAPANESE

私はこの文章を同じに保たなければなりません

BACK INTO ENGLISH

I have to keep this sentence the same

INTO JAPANESE

私はこの文章を同じに保たなければならない

BACK INTO ENGLISH

I have to keep this sentence the same