How can one tell whether his/her novel will be popular or not before actually writing it? How does he/she make sure that people will like and read the novel they are about to start working on?

As others have said, there are no guaranteed ways to know you have a hit before you put it out there. But one step I always use is to involve a group of beta-readers as I complete my manuscript. I usually find three to five people I know will read my work and give me honest and clear feedback on it. I make it clear to them they don’t need to worry about the usual ‘editing’ things, like grammar, spelling, etc., because that will be taken care of later. I want them to tell me if and when the story is confusing, or find themselves looking to see how many more pages are in a chapter, or anything else that relates to the experience of reading the thing. I then use their feedback to review and make any changes I think I need to make.

That might help a bit on the “liking” part. The “reading” part also gets into how you package, market, and promote the thing once you publish it. That’s an entirely different kettle of fish…