Shrewd Tactician (Combat)Source Inner Sea World Guide pg. 289 (Amazon)
Your dealings with pirates, thieves, and assassins have taught you to be exceedingly careful.
Prerequisites: Alertness, Combat Reflexes.
Benefit: Opponents do not gain a +2 bonus on attack rolls for flanking you, although they can still sneak attack you. You also gain a +3 bonus on Sense Motive checks made to resist a foe’s Bluff checks to feint in combat.Source Weapon Master's Handbook pg. 25 (Amazon)
When an opponent attempts a feint against you, you can spend up to 5 stamina points to increase the DC of the skill check made to feint by 1 per point of stamina spent.