Since I do not have time to exercise, do you think that I can lose weight only by having a strict fitness regime?

yes sure you can lose weights through out the diet program but if u can add workout even at home that will be better and will speed up the results

it depends. i loose weight by taking long walks so it depends on your body.

If you cannot exercise then you cannot burn calories, then only way to loose weight is to reduce calorie intake, this way body can use thareserve energy which is in form of fat.