相信 means 'to believe' or 'to trust', and is a common transitive verb used to express confidence in the truth, reliability, or ability of someone or something. The character 相 (xiāng) here carries the meaning of 'mutual' or 'each other', while 信 (xìn) means 'to trust' or 'faith'. Together, 相信 emphasizes a mental commitment — not just passive acceptance, but active confidence grounded in experience, evidence, or relationship. It’s frequently used in everyday speech when affirming faith in people (e.g., a friend’s promise), ideas (e.g., scientific facts), or outcomes (e.g., success).

This verb often appears with objects like clauses introduced by that-clauses (e.g., 我相信他会来), nouns (e.g., 我相信他的判断), or pronouns. It can also stand alone in responses (e.g., '我相信。') to convey affirmation. Unlike the more formal 信任 (xìnrèn), 相信 is neutral in register and widely appropriate in both spoken and written contexts — from casual conversations to news reports.