YOU SAID:

the man has no credibility

INTO JAPANESE

その人には信用がない

BACK INTO ENGLISH

The person has no trust

INTO JAPANESE

その人は信頼できない

BACK INTO ENGLISH

That person can not be trusted

INTO JAPANESE

あの人は信用できない

BACK INTO ENGLISH

I can't trust him.

INTO JAPANESE

彼を信じられない。

BACK INTO ENGLISH

I can't trust him.