I thought this was clear in the final scene itself. Then again, I've only ever seen the friendship version. Serious question: why did you think otherwise?
Why do I think he tried to kill me twice?
Because I lived despite him at the Conclave.
And because he "could" have removed the Mark earlier... and, if he could not... he could have come clean at the very beginning of the game.
I have a HUGE problem with him lying to me for a year...
Had he said, at the very beginning of the game: "I am such and such... this is what happened..." You would hear a VERY different opinion of Solas from me.
IF he is simply a victim of "shock" writing.. then shame on Bioware. In fact... if this is the case, then I really question whether or not to even continue with Bioware stories... cause I find this kind of writing unforgivable.
Otherwise, I consider him a manipulator and liar who tried to kill me TWICE... but discovered that the second time, he could use me instead, and kept me alive to serve his purposes.
I actually cannot see it any other way.
@Xerrai: And yet none of that slaughter stops his fanbase.
Honestly.. he would make Khorne proud.