I gave it a lot of thought... So much thought for such a question that looks simple at first... "What a Real Duelist means?"...
It looks simple, yet nothing could be more complicated than that. It could mean that Real Duelist is a good Warrior... However can that be accurate? Being a good Warrior means that you defeat your enemies, you make good strategies to stop your opponents...you protect your comrades and subordinates in battle.
However is that enough?
No. Real Duelist is deeper. Does it mean beaing a good Friend? Protecting your friends, putting their safety above yours...save them no matter the cost or whatever damage you take yourself