The buyer most likely has been given the estimate, unless you have excluded Germany from the countries you ship to. You can easily check what the buyer sees by logging out of ebay and logging in using other than your selling ID. Go to the listing and under Shipment and payment select Germany. You should see your rate(s).
Then send him the message with your shipping rate. You can also explain to them where they can find the rates and possibly include the screenshot (after you completed the above steps)
PS make sure your rate is set up correctly, based on weight, dimensions etc. before you respond to your potential buyer.
