My Macbook won't allow me to delete files that's in my trash! ㅠㅠ

You really don't need to do "secure Empty Trash." Just empty the Trash. If you don't have permission to access some items that means you shouldn't be trying to delete them or you are trying to delete a file you don't own.

If your external drive is used only on your Mac, then it should not be formatted ExFAT. It should be prepared as follows:

Drive Partition and Format

1. Open Disk Utility in your Utilities folder.

2. After DU loads select your hard drive (this is the entry with the mfgr.'s ID and size) from the left side list. Click on the Partition tab in the DU main window.

3. Under the Volume Scheme heading set the number of partitions from the drop down menu to one. Click on the Options button, set the partition scheme to GUID then click on the OK button. Set the format type to Mac OS Extended (Journaled.) Click on the Apply button and wait until the process has completed.

4. Select the volume you just created (this is the sub-entry under the drive entry) from the left side list. Click on the Erase tab in the DU main window.

5. Set the format type to Mac OS Extended (Journaled.) Click on the Security button, check the button for Zero Data and click on OK to return to the Erase window.

6. Click on the Erase button. The format process can take up to several hours depending upon the drive size.

Try restarting the computer. Then again try to Empty the Trash. Do you still get the error? What are you trying to delete?

OK, then leave it.

Did you restart the computer then try deleting? Did you get the same error? If you did, then do the following:

Visit The XLab FAQs and read the FAQ on solving Trash issues. You can also try using Trash It! 5.1 to fix the problem. Or you can try this:

Open the Terminal in the Utilities folder and paste the following at the prompt:

sudo rm -Rf ~/.Trash

Press RETURN. Enter your admin password when prompted. It will not echo to the screen. Press RETURN again.

First, never use the shell (Terminal) to empty the Trash. It's dangerous and unnecessary, and it usually (as in this case) won't work.

When you disconnect the drive, are you able to empty the Trash normally?

There are some who argue that using the Terminal to empty the Trash is dangerous. This is simply not so. What is dangerous is not being careful when typing in a command line on your own. But pasting one that has been tested is not dangerous and it works in almost all cases, contrary to the opinions of some. Statements such as "dangerous and unnecessary" or "doesn't work" is simply another person's opinion. It is not a statement of fact.