When his pregnant wife is murdered, a grieving husband must kill the man responsible before joining her in the afterlife.

Sorry, just saw that you mentioned it's actually a comic. Still, without a hook it's a tired formula.

Poromaa's suggestion is good - the vengeance killing is the qualifier for the man's soul to pass onto the afterlife. If you've got something like that in there, it makes the story unique - gives it a hook. Without it, the film just sounds like a bog standard revenge flick.

Like mmckean says this logline lacks something. Nothing is at risk here since he will die even if he tries or not. Also he won't get her back revenging the murder? Not knowing your story I could come up with a new one that would put something at stake.

"When an african tribal priest pregnant wife gets killed, he must obey the gods by revenge the killing to secure a place with his beloved in the afterlife"