YOU SAID:

Declan is not the father.

INTO JAPANESE

デクランは、父ではないです。

BACK INTO ENGLISH

Declan is not my father.

INTO JAPANESE

あの人は私の父じゃない

BACK INTO ENGLISH

That man is not my father.

INTO JAPANESE

あの人は私の父じゃない

BACK INTO ENGLISH

That man is not my father.