You can avoid all of this messy plurality by just deleting the items without any message and giving the user a really good Undo facility. Users never read anything. You should build a good Undo facility as part of your program anyway.
You actually get 2 benefits when you createe a comprehensive Undo facility. The first benefit makes the user’s life easier by allowing him/her to reverse mistakes and minimise reading. The second benefit is that your app is reflecting real life by allowing the reversal of non-trivial workflow (not just mistakes).
I once wrote an app without using a single dialog or confirmation message. It took some serious thinking and was significantly harder to implement than using confirmation-type messages. But the end result was rather nice to use according to its end-users.