You’ve learned to use your quickness in place of brute force when performing combat maneuvers.
If I have Weapon Finesse, can I apply my Dex bonus to my combat maneuver checks instead of my Strength bonus??
It depends on what combat maneuver you’re attempting. Disarm, sunder, and trip are normally the only kinds of combat maneuvers in which you’re actually using a weapon to perform the maneuver, and therefore the weapon’s bonuses apply to the roll. Therefore, if you’re attempting a disarm, sunder, or trip maneuver, you can apply your Dex bonus instead of your Str mod on the combat maneuver check (assuming you’re using a finessable weapon, of course). For other combat maneuvers, you use the normal rule for determining CMB ( Str instead of Dex).
Pathfinder RPG Core Rulebook. Copyright 2009, Paizo Publishing, LLC; Author: Jason Bulmahn, based on material by Jonathan Tweet, Monte Cook, and Skip Williams.