Name for a real bad city. I recall watching a show. All the people were dead waiting to go to Heaven, or hell. Some bad guys went there to hide out… not knowing what it was. The name of the town was, “Paridise.” If you stayed there three day, you either went to heaven, or hell. Just maybe you should give your city a safe, good sounding name. Morginville. Morg in ville?
I always like a somewhat ironic name. Like how the community in Jaws was called Amity. I also think the founders of the place would be far more likely to give it an aspirational name, rather than the opposite. And if you like the gag you can even make it a point of comment for various characters, using it like a thematic foil. So call it Hopeton or Fraternia, or something along those lines that better suits your setting. Just think of what characterises your city (treachery, crime, etc), think of their antonyms (trust, justice, etc) to start your wordlist, expand the wordlist by using a thesaurus and/or etymological dictionary (or words from other languages, perhaps those endemic to wherever the town is), then play around with them until you find something that fits!
Most real world cities are name after their location, a religious icon, or a founder. As for assassins, if they served the same function as the police or city guard does, then it could work. In other words, crimes or perceived crimes are punished by the actions of assassins. Of course there would be retaliation, so the city would be a pretty bloody and dangerous one.
I second using a city name generator And I find it good to meld two (or even three) names together if you're not keen on the original result. That can give you some interesting names