Questioning Beliefs is an Act 2 companion quest for Fenris in Dragon Age II.
Acquisition
The quest becomes available at 50% friendship or rivalry.
Notes:
- When you start Act 2, you will have both this quest and Speak to Fenris active if the amount of approval is high enough. You will always Speak to Fenris first. After completing that quest, Questioning Beliefs will trigger the next time you talk to him.
- This quest can be completed both before and after A Bitter Pill. You can pursue a romance with Fenris in both cases, but the conversations will be slightly different.
Walkthrough
Fenris tells the story of his escape from Danarius. Listening to his story and choosing only diplomatic responses nets 
Fenris: friendship (+15). There is no approval change if you flirt.
Note: 
Choosing all flirt options and will also grant Fenris: friendship (+15)
Choosing all flirt options and will also grant Fenris: friendship (+15)
Note: If Hawke is planning on romancing Fenris, this quest is a necessary prerequisite for that. The romantic options following Fenris' story seem to be what instigates the romance relationship. (The conversation here is what grants the Flirtatious achievement, not the one in A Bitter Pill.)
Choice 1
- Investigate "You want to discuss it now?"
- Choice 1
- Flirt "Tell me anything you like."
- Choice 2
- "Why not?"
- Choice 2
- "Not really." Allows you to do the quest at another time.
Choice 2
- Diplomatic "He abandoned you?"
- Humorous "Sounds like fun."
- Aggressive "So it wasn't your choice."
Choice 3
- Diplomatic "Didn't you want to leave?"
- Humorous "I can see where this is going."
- Aggressive "And you refused to go."
Choice 4
- Diplomatic "What? Why?"
- Humorous "Old habits die hard?"
- Aggressive "So much for freedom."
Choice 5
- Investigate
- "You didn't stay in Seheron?"
- "Why didn't you leave earlier?"
- "You regretted killing them?"
- "How did you get away?"
- Diplomatic "Thank you for telling me."
- Humorous "It's a good story."
- Aggressive "Denarius should be dead."
Choice 6
- Flirt "Just friends?"
- Choice 6.1
- Diplomatic "I agree."
- Humorous "Or too much wine."
- Aggressive "Let's not go crazy."
Choice 6.1
- Flirt "I'm willing."
- "This is a little sudden."
- End romance "Stop right there."
Note: His closing statement will vary depending on your dialogue choices.
Note: If the game believes Hawke to be in a relationship the last option may not appear and the romance scene after A Bitter Pill will not trigger. This may happen after sleeping with Isabella, even if you selected to break the relationship up. PC users can use the console to set the romance flag of the other characters to "Ended"