Followed the wiki and all web sites. Every conversation happened as expected. Found 50% of Red Jenny caches as well!
Checked the save file, approval sits at 125 max! She will not trigger.
This has happened for several characters as well. Qunari, dwarf and human. Rogue and mage.
Every quest has been done, all the war table missions too. Just came out of the fade where approval hit maximum.
What the hell do I do?
I'm assuming you're having trouble with the romance?
If so, I had the same issue and the solution (if you haven't done this already) is when you go talk to her back at Skyhold, hit "I'm interested in you." She'll tell you "Let's travel around more, yeah? Let me get to know you better." Which is sort of a hint.. so chat her up again, and exhaust every single dialogue option available. Ask about the red jennies, etc. The only one that doesn't require it is the option of "You're odd for an elf" in fact judging by her tone she does get shitty but you can redeem yourself by flirting and get some extra approval. But yeah, just talk to her and like I said, every single dialogue option that is available.
Now if that doesn't work you are most likely bugged. Hope that helps. 