Mr Grigorii,
it is delightful to see that there is growing number of people in the city with an appreciation for hand-to-hand combat. I, myself, am a proficient boxer -- I would be delighted to practise with one of you some time. You will understand that a man in my position cannot risk fighting unknown people in places that are not absolutely secure, so I probably will not be able to attend your meetings; but you are welcome to come to Serena Tower to fight me. We have a wonderful duelling chamber here that should serve our needs quite nicely.
Sincerely,
Agent Hector K.L. Best
Winner of the Best Boxing Wizard Youth award of Waterdeep Mage Academy in 1371 DR