assassin's all depend on their stuns so your #1 priority needs to be keeping you opponent stunned as much of the fight as possible. the real strategy is knowing what to use, when, and on what class. For example, Gladiators its ideal to let your stuns off sporadically throughout the fight using FE and aether twist to avoid their powerful knockdowns. while with clerics/chanters you want to hold your stuns till they start trying to heal and use ambush/pain rune/binding rune to prevent them from healing themselves. i will post an excellent guide to sins for you to look over when i can find it.