Wondering if there are any fault inside

Yes, you have some fault inside. Or, in better English, your writing is not very good yet. Your text is confusing. I'm not sure what you're trying to say at all, so this could be completely wrong…

You know that there is more than one way to say things in English. The words you choose help to define the mood of what you write, and the way you string the words and sentences together help the reader to follow the thoughts you are trying to convey… So what I have done here is just one way to improve your paragraph. If you have specific questions about what I did and why, please ask - I'll keep checking on this thread.

Despairing, he sat at his desk. Never would he have predicted that his friend would be so brutal, so depraved. What can he do? Maybe keeping silent was the only way he could recover his old level of comfort. All of a sudden, a strange and ominous atmosphere seemed to permeate the ancient mansion. He heard a knock at the door. Panicky, he shouted, "Come in!" His partner entered. Both of them were ruined, completely without money. They recalled that their original thought was to become rich together; who could have predicted this outcome? Opportunities buzzed like flies around them and there was no way to take advantage of them. Although they had done their best to regain the money they had lost, they did not realize they had been cheated. This story tells us - DO NOT RISK TOO MUCH AT ONCE. YOU MAY LOSE IT ALL.

However, this story doesn't really tell us much at all. Why is he at his desk? What did his friend do that was so brutal and depraved? What should he keep silent about? Who deceived them, and how? What did they risk, and how did they lose it? If the answers to these questions are not important to telling the story, you should not bring them up. Finally, DO NOT TOO FERVENT IN RISKY ADVENTURE has no verb. It is not a complete statement.

Please keep practicing and keep asking questions. Other posters have improved their English skills by doing this. If you simply ask a single question and never come back, we can't be very much help even if we want to! Keep up the good work!

Nevermore.

Wondering if there are any fault inside
Two points:

1) One of the main problems here is misuse of prepositions. Prepositions are difficult in most languages; English is no exception.

2) Not to be rude, but is this for real?