Why are you interested in this job ? How do you approach this interview question ?

I would talk about the company and what they do and their services which are talk of the town and how their image in the market attracts me as a Job seeker of that position posted on the career page.

I would then talk about how my skills, talent and experience (that the job requires to be done) would be of a win win suitation for both business and self.

I would be really excited to learn more and explore the new challenge and see how I’ll be able to contribute the firm.

People from the HR department would always want to know what drived/drives you to do things. So this is a very tricky question, there's actually more to it than just why are you interested in this job. Believe me they have seen thousands of CVs  and interviewed way much already to just ask a simple question.  This question gauges your motivation, attitude, tenacity, work ethics and more. You will have to come prepared and atleast research a bit about the company and the role. Try as much to avoid comparison or bad mouthing your previous employer, this will not say much of them but of you. 

Interested in the job, Means an opportunity to learn, Contribute.. progress with the Vision of the Company aligned to the Job. 

FIRST U NEED TO KNOW WHAT THE COMPANY DOES, WHERE DOES YOUR POSITION OR YOUR INTENDED POSITION LIES WITHIN THE ORGANIZATIONAL STRUCTURE, WHAT ARE ITS CONTRIBUTION TOWARDS TOWARDS THE OVERALL OUTPUT, MISSION AND ITS VISION. AND ONE SHOULD ALSO BE ABLE TO RELATE THE POSITION WITH THEIR PERSONALITY, EXPERTISE, SKILLS AND QUALIFICATIONS WHERE POSIBLE.    

I see this job will be the first suitable stage on my target stair I would like to go further to achieve my success