The first card in this reading is the King of Cups, which represents a person with a great deal of resources and power. This means that you are able to change many things within your business and have the ability to greatly influence the earnings you could achieve. If you will invest your resources intelligently, there is a high probability of profit.
The reversed Eight of Swords speaks of difficult situations that need to be dealt with. This means that even if you have the resources to change things, you can't fully control all the elements involved in your business. There may be unforeseen events or other factors that can hinder your success and limit your possible earnings.
Finally, The Star is about hope and faith in the future. This means that you may not be aware of something important to your financial success. This could be valuable information on how best to manage your long-term trading or even the existence of new opportunities that could improve your earnings.
In conclusion, these three cards suggest that you have a high probability of earning a big profit through long-term trading if you use your resources intelligently. However, you will face difficult situations and not be aware of certain important factors that could affect your earnings. So, the answer to the question is: Yes, but with caution.