Now this isn't a likely scenario for anyone's book, but I always love this sort of twist. So let me set it up and ask you all.
One of the most agonizingly painful scenarios is when character A is betrayed by the lover, really betrayed. And you can really milk that for angst and pain and all that good stuff.
However, there are a few of us who want to make it EVEN WORSE. The 'betrayer" is actually doing it to save the betrayed, only this requires that everyone think it's betrayal.
Let me set it up so I can use he/she pronouns. I'll summarize the world's most tearjerking ending, of Dedicated Villain, by Patricia Veryan.
Roland is a "dedicated villain," a charming rogue who manages to ingratiate himself with a traveling troupe of performers who are (he knows) trying to leave with Prince Charley's gold to return it to the donors.
Roland of course wants to steal this gold from them. Along the way, he becomes friends with everyone and falls in love with Fiona, one of the girls in the troupe. They have no idea he's anything but a nice guy who wants to help them. Well, a couple of the men are suspicious of him because he's so smooth and handsome and all that.
Anyway, in the end, he realizes that the Evil Army Officer has figured out that the troupe has the gold and is going to arrest them (and after the Bonnie Prince's rebellion, arrest meant they'd be hanged). To save them, he has to make them all believe that he has betrayed them and stolen the gold.
And they do, realizing that he never was who he said he was. So he's sacrificing his own redemption (getting these good people to care about him) by exploiting the terrible reputation he thought he'd escaped. And he's sacrificing Fiona's love, but so that he can save her life.
Sigh. It is so wonderful.
Anyway, the question. If you've set up this sort of double-cross, this fake betrayal, would you (in the "betrayal" scene) hint somehow that there's something off about his actions, so that the reader kind of doubts that he's really betrayed them?
Or would you let the reader have the same experience as Fiona, thinking that Roland has really betrayed them?
And why? And how?