YOU SAID:
The only one who is in this house and he was so very good.
INTO JAPANESE
この家にいる唯一の人、彼はとてもとても良かった。
BACK INTO ENGLISH
The only person in this house, he was very good.
INTO JAPANESE
この家で唯一の人、彼はとてもよかったです。
BACK INTO ENGLISH
The only person in this house, he was very nice.
INTO JAPANESE
この家で唯一の人、彼はとても素敵でした。
BACK INTO ENGLISH
The only person in this house, he was very nice.
That didn't even make that much sense in English.