faithful, upstanding

(まこと) Faithfulness and fidelity to your boss or superior person.
(せいじつ) Fidelity to your lover. (used as noun or na-adjective)
(しょうじき) Integrity in your dealings with everyone.   $$$
(けんじつ) Reliability. 堅実 doesn’t have the moral aspect of words like 誠 or 誠実. 堅実 is more like, someone who works steadily, who doesn’t take chances, who is always on time, who is rock-solid and conservative.
(ちゅうじつ) Someone who is faithful in doing his/her duties. Also means like a movie which is faithful to the book, or a translation which is faithful to the original. Or even a forgery which copies the original dollar bill completely well.