These words all mean to believe that sb/sth will do what you hope or expect of them or that what they tell you is correct or true. 以上各词均含相信、信任、信赖之义。

• trust to believe that sb is good, honest, sincere, etc. and that they will do what you expect of them or do the right thing; to believe that sth is true or correct 指相信、信任、信赖：◆You can trust me not to tell anyone. 你可以相信我不会跟任何人讲。◆Don't trust what you read in the newspapers! 别相信你在报纸上读到的！
• depend on/upon sb/sth (often used with can/cannot/could/could not) to trust sb/sth to do what you expect or want, to do the right thing, or to be true or correct （常与 can/cannot/could/could not 连用）指相信、信赖、指望：◆He was the sort of person you could depend on. 他是你可以信赖的人。◆Can you depend on her version of what happened? 你相信她对所发生事情的描述吗？
• rely on/upon sb/sth (used especially with can/cannot/could/could not and should/should not) to trust sb/sth to do what you expect or want, or to be honest, correct or good enough （尤与 can/cannot/could/could not 和 should/should not 连用）指信任、信赖：◆Can I rely on you to keep this secret? 我能相信你会保守这个秘密吗？◆You can't rely on any figures you get from them. 你不能相信从他们那儿得到的任何数据。

trust, depend or rely on/upon sb/sth? 用 trust、depend 还是 rely on/upon sb/sth？

You can trust a person but not a thing or system. You can trust sb's judgement or advice, but not their support. You can depend on sb's support, but not their judgement or advice. Rely on/upon sb/sth is used especially with you can/could or you should to give advice or a promise. * trust 的宾语可以是人，但不能是物或制度；trust 后还可接 sb's judgement 或 advice，但不能接 sb's support；depend on 后可跟 sb's support，但不能跟 sb's judgement 或 advice；rely on/upon sb/sth 尤与 you can/could 或 you should 连用，以给予建议或承诺：◆I don't really rely on his judgement.◆You can't really rely on his judgement. 你不能真的相信他的判断。

• count on sb/sth (often used with can/cannot/could/could not) to be sure that sb will do what you need them to do, or that sth will happen as you want it to happen （常与 can/cannot/could/could not 连用）指可信赖、依靠、指望（某人做某事）、确信（某事会发生）：◆I'm counting on you to help me. 我就靠你帮我啦。◆We can't count on the good weather lasting. 我们不能指望这样好的天气会持久。
• believe in sb to feel that you can trust sb and/or that they will be successful 指信赖、信任、相信某人会成功：◆They need a leader they can believe in. 他们需要一个可以信赖的领导。

Patterns

• to trust/depend on/rely on/count on sb/sth to do sth
• to trust/believe in sb/sth
• to trust/rely on sb's advice/judgement
• to depend on/rely on/count on sb's support
• to completely trust/depend on/rely on/believe in sb/sth