Hey, not bad, i got the main idea you were trying to get accross. I fixed anything that created any confusion in what you were tring to say


One day, a man named Dr. Oldvild came to Poirot and said that one year ago his wife died because of a gastric ulcer. She had been ill for quite some time. She was a very well-to-do woman and left him a large inheritance. Because of this, rumors began to form saying that he poisened her. He started to notice that people were now avoiding him and are becoming unfriendly with him. Also, he said, that in spite of the fact that he was good husband to her, he was in love with another woman, his pharmacist. His business was now suffering and that he himself has had nothing to do with these rumors. He said that he wanted to propose marriage to this woman, but he was afraid of what people would say to him had he gotten rid of his
wife in order to marry her. So, because of all these rumours, he decided to turn to Poirot. Poirot and his valet went to the country to investigate the case. He talked with some of the locals, the postmaster, the pharmacist, with Dr. Oldvild's maid, and with some other people since they had the most inveterate gossip in the country. Though maybe unintentionally, the maid accused Dr. Oldvild's of poisoning his wife to make it possible for him to marry the pharmacist. Poirot ordered an exhumation of Dr. Oldvild's wifes body to have an autopsy done to find out the cause of her death and to finally put a stop the rumours. Poirot had guessed, that this maid had fallen in love with Dr. Oldvild and that she had formed the impression that if his wife had died, he would ask her to marry
him. Because of this, she had begun adding arsenic to the wifes food in small doses. When she died, the maid found out that he loved his pharmacist. But Poirot didn't have any evidences to support this idea. So he ordered his valet to look after the maid. So in the end, it turned out that when Poirot ordered to exhumation of the body, the maid, driven by anger and jealousy, put arsenic into pharmacist's handbag with the purpose of setting her up, but the valet saw all of this. She confessed her crime.

I did not change any of the information given origanlly, I just rewritten anything that did not flow naturally. As most know, there are many different ways to write this paragraph, this is just one example.