This page contains all the information you need on how to begin, and keep, a romance with Thane Krios.
Recruit Thane and complete Loyalty Mission
Thane is one of three potential romances you can do as a Female Shepard. Before you get started, you’ll need to recruit him to your team by completing Dossier: The Assassin followed by his loyalty mission, Thane: Sins of the Father.
You’ll only be able to pursue a romantic relationship with Thane if you successfully prevent Kolyat from killing Talid in the loyalty mission. This is done by informing Thane of Talids whereabouts before the timer runs out. If successful, speak with Thane onboard the Normandy and say “I want to talk about you” followed by “I want you, Thane” to get the romance underway.
Once you’ve completed another mission, return to Thane and say the following, “I want to talk about you” and “I care for you too” to progress the romance. However, if you’ve been courting either Jacob or Garrus you’ll need to cut it off with the to continue with Thane. Now return to Thane later on and say “I’m fine” to secure the relationship with him.