Often people use the terms 'fate' and 'destiny' interchangeably but there is a subtle difference between the two. Fate means the preordained course of your life that will occur in spite of your actions. Destiny, on the other hand means a set of predetermined events within your life that you take an active course in shaping. In other words, fate is something you have no control over, whereas destiny is something which you can shape with your actions. Simply put, you can overcome your fate with your actions and hence shape your own destiny.
The way people view fate and destiny can have a profound effect on how they live their lives. If people believe that their lives are a result of fate and that there is no way to change this, then they are likely to become passive and adopt a "fatalistic" attitude, becoming observers of rather than participants in their lives. People who believe in destiny take active roles in their lives.
Lets see how this difference has played out in the lives of MJ and Tara.
Before he met Tara, MJ has, by and large, been fatalistic. He resigned himself to his death as he wanted to fulfil the promise he made to the woman he considered his mom but who did not reciprocate his feelings. Yes, he took the decision to take the blame, but it was in the interest of saving the life of his brother. In other words, he tried to shape the destiny of his brother while letting fate take its own course with regard to his own life. He did not care what became of his life for he felt his life was worthless to all but his father. He thought that he was minimising his father's loss which, in his view, would have been greater had he lost his biological son instead of his adopted son.
When his father wanted him to get married, he passively accepted, since he wanted to grant that as a parting gift to the man who cared for him all his life. Again he let fate dictate his life. He wasn't silent though. He tried to intervene and shape the destiny of the woman who had the misfortune to be his wife, even if it meant portraying himself as the demon he wasn't. Even after he realised that he loved this woman he kept his feelings hidden letting fate deal with him.
Tara, on the other hand, always fought her fate and shaped her own destiny. MJ's alliance had initially come for her sister which her mother had declined but Tara chased Jairaj and offered herself as the daughter-in-law he was looking for. When she realised she was to be married to a convict, her initial impulse was to run away but she stayed back and got married to the man for the sake of her family. She initially suffered MJ's violence in silence but ironically it was MJ himself who gave her the will to fight back which she did, and how! She did not hesitate from hitting back hard where it hurt him the most and in the process won his admiration for her spirit.
When she came to know that MJ was innocent of the crimes he was accused of, she went all out to prove it, even with no help from anyone, least of all her husband. She did not let fate take its course and risked losing her mother's love and care in the process. She took charge of both her life as well as her husband's and shaped their joint destiny. Against all odds she helped trace Radha which, in turn, enabled MJ learn about the happenings of that fateful night which had changed the course of his life. On learning that the crimes he was taking the blame for never really happened, MJ was free from fulfilling the promise he made to his mother and the man could finally admit his feelings to his wife. Thus, MJ's and Tara's destiny turned out for the better because of Tara's spirit of never giving up.
Once they were united in love, Tara's positivity rubbed off MJ and since then we have been seeing him shape his destiny which is now intertwined with Tara's. Fate in the form of RP-Kala is still a formidable force and has been putting spokes in their wheels but then the combined force of MJ and Tara are more than up to the task.
Things at present look bleak as fate seems to be winning this battle but the war isn't over yet. With MJ and Tara at the helm, destiny shall prevail.