I can't believe that anybody can question his desire to come in United.
1. Personal CV. United is one of the biggest clubs in the world. I have huge respect to Spurs but they are far from United in everything( except points
). To be a manager of clubs like United, Barca, Real is honour for every manager. It is something what is your goal when you start in that business.
2. With United he can win titles. With Spurs he can't. He can be in top 4 but to compete with City, Chelsea, Liverpool and United he must spend money. And in Spurs he can't do that. He can't spend 100mil on one world class player.
3. We can give him (much) bigger salary.
Of course, i am presuming that he is like everybody else in sports. That he wants glory, money and success. If he is different type of person who is happy to work in calm environment without too much stress then ok, my mistake.