"Sonnet x by John Donne is like a dialog where the speaker speaks with the personification of the death. The death is pridje and the people says that it is "mighty and dreadfull". The poet says that the death don't have any power on the human because his faith says that the human don't die even if the death think "to dost over throw". Donne in this sonnet describe the death and the "rest and sleep" this two things give to the human "much pleasure" and then the poet says that the best human are the away by death."

I can't correct your English because I don't know the work of John Donne. Maybe if you could answer to my questions I could help you. The Sonnet X is a dialogue or a poem? You should mentionne that it will be better and clearer. For the first sentence, you can't say that the poet speaks with the personification. The personification is a figure of speech. In this sentence, you should explain the main subject of the poem so the death (if I correctly understood). For the sentence number 3, it will be better to say "The speaker explains that the death doesn't have any power on the human". I don't understand what do you mean after. You have to try to refrase. It's better to write "the speaker" than "the poet". 

For sentence number 4, you should write " In this sonnet, Donne describes the death and the "rest and sleep" these two things give to the human "much pleasure". We can't write "this two things" you must write "these two things". 

 I hope I helped you a little bit. My advice will be if you can't speak fluently english, you have to make shorter sentences with basics words. For your information I'm not English.