This is unlocked in Chapter 3.
Unlike Vinh this seems to require important choices in previous chapters.
Mainly in Chapter 1 when you talk with Amanda make sure to ask for a DATE and not just hang out. I believe that is the only choice that matters, but to be safe any time you talk with her just be friendly/ flirt.
In Chapter 3 talk with Amanda in the Living world until the last choice and KISS HER. Now go to the Dead world and talk with Vinh and for the last option PULL AWAY. Now leave the bar in the Living world for the achievement.
If you asked Amanda for the date in Chapter 1 you can unlock all romance achievements by doing chapter select - explore scene - spin - Nobody Wants to Drink Alone. Use RB to skip dialogue to make things quick and choose whatever outcome you want.