Go to the training area again. This time you will train hitting and blocking together with Whisper. Next, you will have a little sparring fight. After the Guild Master is gone, wait for the black-hooded teacher to appear. Talk to him and take the test. If you fight Whisper and get an A+, you'll be rewarded with the Katana.
You will have to go through similar training procedures concerning ranged weapons and Will using (you can take additional tests each time for some handy rewards). Guild Master will tell you that you're ready to graduate. Don't agree yet, as there are some things to do first. Next to one of the bridges is a mysterious apprentice who'll tell you to get rid of the birds around the guild. Shoot them with your bow (you'll get some evil points for that). Pay Whisper a visit in Guild Woods. You'll have an opportunity to slay your first bandits. Once you're done go back to the Guild Master and finalize your training. Your final exam will be to go to Guild Woods again and 'fight' Maze there - meaning hitting him a few times every way possible (melee, ranged, Will). Finally, you'll become a fully legal and mature hero. Well, that wasn't too hard, was it?