Kin, if they are able to write English, they will more than likely be able to speak the language well enough for you to have a simple conversation. Generally, all though not always, you will be able to speak to someone in a German business using English - in Europe, it often seems to be the default between Dutch, Germany, Belgian speakers (this is a broad generalisation but I'm yet to make a phone call to a German business where I couldn't at least have a very basic chat).
At this stage, I'd say you have a 50/50 chance of it being genuine but my hunch would be that it isn't. If you are a business and you want to buy a car, you call, you don't email.
