Which one's right?
Is he going to kill me, John wonders?
Is he going to kill me, John wonders.
Neither. It's:
Is he going to kill me? John wonders.
or
"Is he going to kill me?" John wonders.
Hello again, Mr Stone! Long time no comms. I spotted this and thought I had to had to suggest that you read a page or two of 'Daddy Love' by Carol Joyce Oates. We all know she's a mastermind, but the way she writes character dialogue/inner dialogue in that book is freaking brilliant. E.g.:
Through her broken jaws she tried to speak. Tried to ask Have they found Robbie yet?
Whit told her no not yet. Not yet was Whit's way of consolation.
At her bedside Whit radiated calm. Elsewhere Whit was crazed.
Whit cradled her in his arms. As much as he could lean over the bed, without hurting her. (But could she feel pain? It was a cotton-batting sort of pain, a roaring in her ears that might have been screams but were muffled.) He loved her very much, he said. Their son would be found and returned to them, he was certain.
You see what she did there? It's dialogue to a point, and you never doubt that you're being told exactly what was said, but at the same time their inner thoughts and impressions (separate and collective) get merged in with it. The whole book is like this, and it creates a kind of intimate, melancholic dream-haze. Occasionally she does use quotation marks, but only to add emphasis to an extra gut-punching piece of dialogue.
Whether that's what you're going for or not, it's definitely a way to tweak--and easily the most intimate 3rd-person POV I personally have ever read.
Check it out!
It's true (preferable, even) you don't need the "wonder" attribution when using italics. If you're really struggling with this, I suggest rewording it more distantly.
He wondered if the assassin was going to kill him.
Or better yet, stop wondering and start acting.
Would the assassin kill him? John fled the scene, not wanting to find out.