YOU SAID:

my jeans are tight and hers aren't

INTO JAPANESE

私のジーンズはきつくて、彼女はそうではありません

BACK INTO ENGLISH

My jeans are tight, and she is not.

INTO JAPANESE

私のジーンズはきつい、そしてそうではない。

BACK INTO ENGLISH

My jeans are tight, and it is not.

INTO JAPANESE

私のジーンズはきつい、そしてそうではない。

BACK INTO ENGLISH

My jeans are tight, and it is not.