Garrus Vakarian must survive the events in Mass Effect 2, specifically, the Suicide Mission (Final Battle).
How to Romance Garrus Vakarian Prerequisite Romance Guide: Garrus Vakarian Information Players will get a chance to interact with them, creating a deeper and meaningful relationship.
Romance in Mass Effect 3 helps the players develop a romantic relationship with their desired Companion or NPC. Romance Guidefor Garrus Vakarian in Mass Effect 3 features a guide on how to romance and have a relationship with Garrus Vakarian.