What Makes Betrayal Unbelievable?

For me, the worst kind of betrayal is the one that has no foreshadowing or reason. For example, Loki's 'betrayal' in Thor: Ragnarok. That had no reason nor plot relevance or any weight to it. All it did was serve to make Loki late to the final battle. However, if the writers really needed that 'last minute grand entrance' they would have had the Grandmaster find Thor and Loki escaping, Loki would then be forced to distract the Grandmaster to help Thor escape back to Asgard and somehow save himself from getting melted and escape later on. But, we're stuck in the universe where Ragnarok has weak character development and motivations and treats everything like a joke.

A close second. Is the betrayal of a character who is like a sibling to the other, but all they get in return for their betrayal is money or status in the enemy army or even just the reassurance that they won't be killed when the enemy steamrolls the mc's forces (even though they never, ever do but the betrayer is stuck with their choice anyway). If you have a relationship that's said to be as close as a sibling, no writer means they fight tooth and nail over bullsh*t or have a rocky relationship or any of the bad sibling relationships. What they mean is that that person is their family in all but blood and they will die before they let anyone seriously harm them. No one with that kind of relationship is going to turn around and take a bribe to murder or assist in the murder of their 'sibling'. The only way this betrayal happens is if a blood family member is threatened but a smart person would tell their sibling friend what's going on because chances are that blood family character is either the love interest of the sibling friend or they see the blood family as their sibling as well and would help rescue them. So really this kind of betrayal never has a solid reason to happen.

Unless there is a literal object or something that physically inhibits the character from letting the sibling friend know in any capacity that something is wrong.

 

I think Judas's betrayal of Jesus is rather hard to believe. Judas saw Jesus give sight to the blind, cure the lepers, raise the dead, walk on water. He had to know there would be CONSEQUENCES to betraying a man with that kind of power.

 

I've heard the idea tossed around that that was exactly what Judas was hoping for. He wanted Jesus to have to defend himself so that he'd unleash his power against his enemies. It would be an interesting motivation, and it's certainly more believable than that he'd do it for just a bag of money.

 

I've read a similar theory, albeit in a fiction book. In the book, Judas wasn't happy with the whole "render unto Caesar" thing and wanted to see Rome, or at least Roman rule, totally swept away and thought that Jesus would do so to save himself.

There was a book I read in which the MC was disappointed by his own side's lethargic response to an alien attack (both sides were multi-system civilizations), so he switched sides and urged the aliens to greater brutality, telling them that it would break the will of the human race to see mass slaughter while knowing that it would finally outrage people enough to take the conflict seriously. Kind of a Lusitania semi-false flag strategy, if you will.