Let's rewrite that:
Good morning, Mr. Irving,
Your mission, Washington, should you decide to accept it, is to compile a series of cultural and historical sketches laying the foundations for tourism policy in Granada and to a considerable extent in Spain in general.
As always, should any of the natives actually read Tales of the Alhambra, the Secretary will disavow any knowledge of your actions.
This record will self-destruct in five seconds.
Good luck, Washington.
I'm not sure that that I'd agree with the generous contributor that there's any translation angle here, but the tinge of semantic uncertainty, amplified by the archaic "only will be", provides yet another delicious khat-shift in perspective for those of us who would curtain a too-bright morning with the night.