Definitions: (1) conforming to fact; real; (2) genuine; pure; legitimate; (3) loyal to a friend, idea, or ideal; faithful; steadfast; (4) honest; sincere; upright; true-hearted; (5) reliable; certain; (6) conforming to an established standard <true north>; exact; precise; accurate; (7) reflecting the essential character <true meaning>; (8) in proper order; in alignment to an important point or ideal; (9) logically necessary

This above all: to thine own self be true.
And it must follow, as the night the day,
Thou canst not then be false to any man.
— William Shakespeare (1564-1616) King Henry IV {1598}

• To know what you know and what you do not know, that is true knowledge. — Confucius [born Kǒng Qiū] (c.551-479 BC) Chinese ethical philosopher
• People are like stained-glass windows. They sparkle and shine when the sun is out, but when the darkness sets in, their true beauty is revealed only if there is a light from within. — Elisabeth Kubler-Ross (1926–2004) Swiss-American psychiatrist