Throughout the course of the story, you will meet many characters, some who can be romanced. The ladies you need to get with are
Madison Saint James
Each of the different women have different personalities, and must be approached differently. For more information regarding each woman, read Office Romance for Mina Tang, Exclusive Interview for Scarlet Lake, Rome-ance for Madison Saint James, and Savage Love for SIE. If you've done everything correctly, you will unlock this achievement when you regain control of Micheal after the scene with SIE.