doubt : 普通用词，多指因证据不足或仅凭证据还不能肯定而产生怀疑，多含否定意味。
- I doubt whether/if I can finish the work on time.
- They had begun to doubt that it could be done.
- He may come back tomorrow with the money, but I very much doubt it.
- I don't doubt his abilities.
suspect : 指猜疑、疑心，肯定意味较多。
- So far, the police do not suspect foul play.
- We had no reason to suspect (that) he might try to kill himself.
- "Do you think she'll have told them?" "I suspect not/so."
distrust : 指疑惑、猜疑，不信任。
- Many politicians are deeply distrusted by the electorate.