hi,i really need ur help to correct my sentence or grammar

Brief presentation of the plot:
Sophia and Charles meet each other in the military, and then they fall in love. Sophia came home before Charles, but they had contact with each other. After the war was finished, Charles went home and asked Sophia if she want to marry him. However, Sophia’s answer was no because of his grandfather’s death, he was murdered. She asked Charles if he could help her to find the murder. Charles and his father and a police officer helped Sophia to find the murder. After searching the house and speak with all those who lived in that house, they find out two persons they thought was the murder. But, in the end they found something mysterious, the murder was a little girl called Josephine.
Characterization of the main character:
Charles:
Charles is the main character in the book. He is honest, loving and helpful man, he loves Sophia and want to be with her, but right now, it is impossible. Instead, he tries to be with Sophia and her family and try to persuade them that there is nothing to be afraid od. Charles seems to be a very calm and quiet man, because Josephine is a girl who irritates everyone with her attitude, but instead Charles try to speak with Josephine and find out what she know about the murder, because she always mentioned that she now who the murder is. Charles is a person who tries to see always the god side of thing, because when Sophie said no to marry him now, then he tried to be more with her, and help her and in the same time be more familiar with Sophia and her family. Charles is a person who is not frightened of something, because he was sure that there was something wrong with Josephine and she was scary and weird, but instead he tried to be always with her and find out what she knew about the murder.
Sophie:
Sophie seems to be something between 20-25 years old. Sophia lives in that crooked house with his parents and two siblings, uncle and his wife, and grandfather's new wife Brenda, and grandfathers sister Haviland. Sophia is a very interesting girl, but she has a problem, she changes her personality very fast when she is afraid or stressed, because at the start of the book she trusted grandfather's wife Brenda and the teacher in that house and told everyone that they are innocent. However, in the end when the situation was bad, she was sure that Brenda and Brown had killed her grandfather and, therefore, wanted them arrested. Sophia is a girl who makes sure that everything is ok, and, therefore, had her grandfather left everything for her and wanted her to take care of the family. One of the arguments her grandfather had written to her was that she is the only one in that house who don’t care about money and fame, and, therefore, all the things her grandfather owned is now Sophia’s. Sophia has a very big heart and wants to take care of everyone in that house; she tried always to take care of her sister and brother because they had problems, but for the most her sister because she was not usual at the all, she looked like she is crazy.
Josephine:
Josephine has a very big self-confidence because she means that she is the best detective ever, and she can find the murder, but sometimes she needs to think more about the situation. She thinks she is beautiful; even everyone’s reaction is bad the first time someone meets her. Because when Charles meet Josephine, he described her like a fantastically ugly girl. Josephine is a smart girl, because she told everybody that she knows who the murder is, and, therefore, attacked herself and destroyed her room because she had written something about who the murder is in a black notebook, which she had in her room. She did this because she wanted attention from her family and the police. She got polices attention more because they wanted her to say what she had written in that black notebook. Josephine is a very good actor, she was the murder from the beginning to the end, but no one mentioned that. There are two arguments who tell us why no one thought that she was the murder. First, because everyone thought that a girl of that age could not kill someone and that is why she killed her grandfather because no one can find who the murder is. Second, because she was always curious to find out who the murder was, and, therefore, no one thought that she could be the murder. Josephine has a heart like a stone, she killed her grandfather because he wanted her to study at home, and do not go to a ballet. Moreover, she killed Nanny because she told her that she could not be a good detective because she is a girl, and girls cannot be detectives. She had written that “I killed grandfather and nanny” on that black notebook without having any kind of blame.
Themes:
I think the themes here is that we should never think that a child could not do something like murder because they are only a child and do not know how they can handle a situation. Agatha has written hundreds of books, and this book is one of those who tell us something about a normal life situation in our time. She mentions that never let your children feel that you make the difference between them, because if they feel that there are differences between their siblings, they can be jealous and do something we never think they can do, it is because after sometimes their eyes and hearts be full of anger and can do everything. That is why we must never break a child’s heart.