Say something like this

I feel my skills and background fit perfectly to your position, and I am passionate on it. (Then you explain why you fit and you feel passionate about it)

As for my current position, although salary is high, I don't feel like to work in the area, not passionate on it either, blah blah....

Hold tight on how your skills and experience FIT the position and how you can contribute to the position!!!!

That is the only thing the hiring manager cares about. He will not give a shit on anything else, like you are not ambitious, you want to spend more time with family ... that is just sheer bullshit to the hiring manager.