Please Confirm You Received Our APT
https://www.fortinet.com/blog/threat-research/please-confirm-you-received-our-apt
For me the email subject, would have me suspicious right from the start.
I confirm nothing, and the Subject having Fw: (forward) in the subject would also have alarm bells ringing. Lets say someone did seek confirmation of receipt the email would hardly have been forwarded. Little things like this should have people suspicious and on their guard.
I also use MailWasherPRO as my first level of check, I don't download email directly. This marks obvious spam and it doesn't download all of the email just a small part (user configurable) and you can set it to be viewed in plain text. This allows you to look at it and the email and headers without triggering any html content (web-beacons/images/tracking, etc.).
The program does flag obvious spam, using various sources and allows you to change/mark emails as spam/clean. Emails marked as Spam are deleted from the email server, for the remainder it calls your email program and the ones you wanted/flagged as good can be downloaded.