Hi shabnamjaan! Welcome to Allnurses.
Choosing a school is a tough thing to do, and very individual. For me, Humber was the most convenient in terms of commute. That was important to me because I won't be staying on campus. If you live in Toronto, maybe Seneca will work better for you. What is most important to you about a school? What are you looking to get out of it?
The 4 year nursing degree is provincially regulated. So you should be getting essentially the same program and education no matter which school you choose to attend. Some people love Seneca, others love Humber and still others will go to whichever school accepts them. You're in an awesome place and you can choose to go wherever you like best.
I would suggest you book a campus tour of both schools and get a feel for the two campuses. That should help you make your decision. Also, search some of the old threads here on Allnurses to see what others have had to say about both programs.
Best of luck in making the decision!