The word 相信 is formed by combining two independent characters, each with its own meaning, to create a new, composite concept. The first character, 相 (xiāng), carries the meaning of "mutual" or "each other". The second character, 信 (xìn), means "to trust" or "to believe". Their combination conceptually merges into the idea of "mutual trust", which naturally extends to the act of "believing in" or having faith in someone or something, effectively visualizing one mind placing its trust in another.