I think your Letter is pretty good.
Perhaps you should stress more on the reasons why you will return after your program's completion. From what I can understand, your reason for the return is that you owe something to your Uncle and to fulfill your societal obligation you will come back and work for your uncle. You should also talk about your plan and aspirations that you wish to implement in your home country and it should be your primary reason for the return.
Also, there seems some discrepancy about what you will do after the degree completion. You wrote "Upon completion of my bachelor’s degree, I plan to further my education by enrolling for an MBA course which goes a long way in furthering my career and satisfying my desire to acquire it." in one sentence and "After my four years at Trent University I return back here with all the knowledge, experiences to continue working at Rocmax Investments which I intend to propel its growth to international levels.". You should clarify this.
And make this part of the sentence more humble "and offer me the study permit to further my studies and progress my career." as it sounds kind of rude. Or maybe its not and its just my perception.
And I am no expert and don't know what goes in the heads of the Visa Officers. Take as much advice from people as you can and make the best out of it. Hope this helps.
