The antonyms for the word "non-believing" can be varied based on context. In the field of religion, the antonyms can be faith, trust, or belief. In the field of science, the antonyms can be acceptance, agreement, or acknowledgement. In the field of politics, the antonyms can be support, loyalty, or allegiance. Additionally, some other antonyms can be optimism, confidence, or conviction. It can be said that antonyms for "non-believing" are words that indicate having confidence, trust, faith, optimism, support, agreement, and acknowledgement. It is important to use the appropriate antonym based on the context to avoid confusion.