Cant delete files on the Trash

Yes!

List the things you've already tried so that we don't suggest them. Also state what happened for each.

Just in case it becomes relevant, also give your OS version.

 

noob

By default the apple operating system can only read to a NTFS drive,it can't write to it
NTFS is windows file systems.

Now that we have that covered.
When you put something from the trash on the external HD,it goes inside the trash folder on the external HD,not on your computer.

So lets piece this together.You can't write to a NTFS but can only read to it.
You are trying to delete something that the from NTFS that the operating system can't do unless you have 3rd party programs.

Now lets say you have to a 3rd party program where your apple can read/write to a external HD.

Your google searches are for probaly trash folder on your computer,which for your case is the trash folder is on the external HD so the terminal commands you may find would only work for stuck items on your computer and not your external HD,so you would need to change the syntax of thoses commands to point to the external HD

 

Hmm...IIRC, The act of sending a file to the trash requires writing to the HD, so how could you delete it if you can't write to the disk?