noun, verb, place word, adverb, modal particle · a written message, piece of mail, or correspondence

我给你写了一封信。

verb, adjective, noun, adverb, pronoun, punctuation · to believe in, have faith in, or possess confidence in someone or something

我不信他说的话。

idiom, noun · information or message about someone or something

他走后一直没有他的信，家里人都非常担心他。

verb · honest, reliable, or sincere in character

信是做人的基本准则，无论如何都不能失信于人。

verb · acting at random, without restraint, or casually

他在公园里信步而行。