This is a personal question, so nobody can answer it for you — but a good answer to it has a shape, and the letter you are about to read tells you exactly what that shape is.
- Name the field, not the feeling. “I want to be successful” is a mood. “I want to design low-cost prosthetic limbs” is a dream — it names a subject you can start studying tomorrow.
- Say what draws you to it. The letter calls this “a passion for a particular interest”. Where did it come from — a person, a book, an incident, a problem you saw in your own town?
- Admit one cost you already know about. Fees, years, distance from home, a subject you find hard. Naming a cost is what separates a dream from wishful thinking.
Sample answer: My dream is to become a wildlife veterinarian and work at a rescue centre in the Western Ghats. It began when a hurt kite fell into our terrace and the nearest vet said he treated only cattle — I realised there are almost no doctors for wild animals near us. I know what it will cost: five years of veterinary study, a seat that needs a very high score in Biology, and probably living far from Coimbatore for most of my twenties. I have started by keeping a notebook of every bird I can identify and by volunteering at the animal shelter on Sundays.