Considering this is only a 5 point achievement, it's actually one of the trickiest in the game. We're not sure why ... Maybe it has something to do with successfully getting a bad guy to respond to 4 different category expressions while he's trying to rip you limb from limb. Nevertheless, there are 3 distinct strategies to use to get it and we'll start with the easiest out the 3.
Strategy 1 - The Fairfax Castle Strategy - Fairly simple in the end, but tough to get to. In order to do this strategy, you must have completed the game and amassed 1 million in gold to buy the Fairfax Castle. After buying the castle and sleeping in the bed one night, the place will be invaded by bandits. Firstly, you must fight your way down to the Throne room and clear the room of all but one bandit (preferably the small weak ones and one that uses a sword and not a gun). Then position yourself behind the throne and there is a place there where for some reason (call it glitchy AI) the bandit will not attack and will just stand there. When you have that sweet spot, stand, make sure he is targeted (red glow) and then use of of the 4 expression types on him (Fun, Flirt, Rude & Scary), one after another. Each one he should respond with a short quip to it and on the fourth the achievement should unlock.
Strategy 2 - The Weaponless Bandit Strategy - Firstly, get down a pack of bandits to the final one and you'll need to shoot his weapons away from his without killing him ... use a weak gun may help? When you do, he'll be swinging his fists around but his reach won't be as good. While he's doing that, get a little distance and use one of all 4 expression types (Fun, Flirt, Rude & Scary) and on the fourth, the achievement should unlock.
Strategy 3 - The Bandit & The Tree Strategy - Tricky, but possible out in the woods (Brightwood maybe). What you need to do is position a tree or clump of trees inbetween you and a bandit, so much that he literally tries to go through the tree to get you. When he's doing that, make sure he is targeted (red glow) and then use of of the 4 expression types on him (Fun, Flirt, Rude & Scary), one after another. Each one he should respond with a short quip to it and on the fourth the achievement should unlock.
Seems a lot for 5 points, but completionists will want to nail this bad boy. It also appears that it doesn't have to be done on the same bandit, so if you must, chose 4 different ones.