While it is true Sun Tzu advocates deception, such deception is only applied in very specific situations that call for a more humane approach. In other words, if you ended up saving thousands of people's lives in the act of lying to the aggressor that your city is heavily fortified, the headline shouldn't be that you are a liar but a nation's treasure. You were not ruthless but rather quite the opposite.
Ultimately the height of inhumanity is the failure to secure the safety and livelihood of your people. This is true in politics as well as in business. Sun Tzu's lessons teach you how to succeed. In order to succeed, however, he wants you to gain the people's trust. Not the disingenuous kind that some politicians and CEOs seem to only possess -- it is the kind that centers around benevolence, not simply profit. (All successful human endeavors are profitable; not all profitable human endeavors are successes.) It is the kind that would make people believe with all their heart that you will not abandon them or betray them. For to do so would be like abandoning and betraying yourself. You and your people are one, the strongest of bond.
Therefore, your words and actions match. While others struggle to achieve their aims by any means necessary, you struggle to achieve your aim in the best way: the honorable way, the way that would have you die in peace if it was today. This is integrity.
In the case of deception employed against your opponent, you can have integrity there too. Before battle, you would have warned your opponent. In fact, you would have exhausted all peaceful options. Yet if he still presses forward, instead of destroying him, you would make him harmless. Is this not benevolence? Anger, regret, and sorrow are all basic human conditions you would be wise to master and control. Hence you "take All-Under-Heaven intact." You would not only likely gain the trust of your friends and even enemies, but also the trust in yourself.