It’s all really subjective. Are they being indirect? Not wording it properly. If it’s an email specifically to you, their behavior or attitude toward you in a work place and what they usually say to you may be similar to what’s in the email. Look out for context clues.
Is this a school question or you’re real life experience?
If you have a specific email that you are confused about right now, you can put that in (just the part you trying to figure out) so I can try to help (only if you’re comfortable with that)