I’d say that, if you want to be successful and make a real contribution to the world, you have to be intrinsically motivated by the work you do, and you have to feel good about spending your days on it. Love might grow–and it’s a wonderful thing if it does–but you don’t need it up front.
The Fallacy of ‘Love What You Do’, Jason Fried, Inc.com
While professionalism and interest are enough for a new hire to succeed in a new position, and professionalism and interest could develop passion in the end, if you can find passion, profesionalism and interest will follow. Not necessarily the other way around.
Related: Interest + Professionalism = Passion