I hope this letter finds you in good health and spirits. As your devoted friend, I could not bear to think you are suffering from, oh, let's say severe indigestion, or some other hideously undignified disease.
Thank you for your graphic and passionate description of your rendezvous with our (as it turns out) mutual friend, Officer Evan Braibant. You should know that ever since I received your lovely letter, Evan is no longer a friend of mine.
Yet allow me to get to the point: by an order from on high, your mission regarding Prince Ansèis has been permanently called off.
So leave the poor lad alone.
Though – knowing you – it is already too late. So just make sure he does not fall for you too hard and do not, under any circumstances, grill him (metaphorically, of course – literally though, do whatever tickles your fancy, it's none of my concern).