I would be sure to do a lot of research on the party sending you these emails. I'm not going to state they are all fake but I've received numerous fake domain requests from parties who claim to either be: A trademark holder, a domain registrar working on behalf of a customer wanting to purchase a domain similar to yours, or a brand name holder.
I've attached an example of what a fake might look like:
(Letter to the President or Brand Owner, thanks)
We are the department of Asian Domain Registration Service in China. I
have something to confirm with you. We formally received an
application on Aguest 21, 2013 that a company which self-styled "FDH
Global Ltd" were applying to register "~REMOVED~" as their Brand
Name and some domain names through our firm.
Now we are handling this registration, and after our initial checking,
we found the name were similar to your company's, so we need to check
with you whether your company has authorized that company to register
these names. If you authorized this, we will finish the registration
at once. If you did not authorize, please let us know within 7
workdays, so that we will handle this issue better. Out of the time
limit we will unconditionally finish the registration for "FDH Global
Ltd".Looking forward to your prompt reply.
If it is a legitimate request, for the most part if you have registered the domain name before they have registered a trademark on that name then your domain is safe. Though there are plenty of other variables to consider if such a case were to go to the courts, such as if and how the TLD was used, if the domain was created in "Bad Faith" towards the requesting party, and more...