Like where they overwrite the file with random data then delete? Can we have that function in this program? Thank you.

I don't think the functionality you want is really required in a torrent client.  If you are on Windows just download Eraser as it does this for you.

I think this functionality would be useful in a torrent client as it enhances user's privacy.

How lazy are you?

Wipe it yourself.

Hum... Is not it a bit rude?

You assume that we are all competent in this matter. Because, it is just a bit more complex that this. It all depends on what the "forever delete" means.

1- for the huge majority of the users, it simply means that it won't go 1st to the Recycle Bin...

2- ... and if it is really a forensic issue, just understand that law enforcement agencies do have the mean to retrieve the echoes of your data, even after the use of a "shredder", except if you take the option of extremely long and repeated r/w above the old data, and using various shredders in the process ...

3- finally, erasing the files won't erase the logs disseminated in your Windows and tmp files and registry, nor the logs kept by your ISP when you access a torrent ...

I think better idea is to use encrypted partition instead of shredding files, however you need some knowledge to do it right.

As JPRC said it really depends on what you mean by deleting forever.  I previously posted a short answer (use Eraser) but will now provide a slightly longer answer.

Firstly, if you never want a file to be found on your computer then never have the file.  This is the only way to guarantee that you will never have the file.

If you just want to delete the Torrent and associated file you can currently do this in Tixati.

If you delete the file out of the Recycle bin (Assuming you're a Windows user here) you are only de-referencing the file.  Imagine scribbling an entry out of a book's index.  The page is still there but it not indexed.  Law enforcement and data recovery services can recover this and most of the time it is pretty easy to do so.

If you use a tool like Eraser (once again assuming you are a Windows user) then it will override the data.  The problem is, it is still possible (but harder) to recover the file.  As the previous person mentioned, the more writes you do the better the hard it will become to recover the file.

You can also use something like Veracrypt to encrypt an entire partition or drive.  This is a step in the right direction but you can be forced to hand over keys by various means.  Veracrypt can help with this by creating hidden partitions.

Even then, if you have a weak Veracrypt password then the encryption is easy to break.  You also run the risk of the file being found in parts of memory (for example, RAM) or on your OS's secondary storage device (for example, your HDD).

So what next.  You can physically destroy the drive.  Using a good drill helps but I have heard of people using acid baths or industrial shredders as well.

If you want a view a file and then instantly delete it then consider a live CD as an OS.  The OS will be booted from a CD and the only place the file (theoretically) should exist is in memory.  RAM is volatile meaning that once it loses power it also loses its ability to hold data.