Cadmus had indeed sent a letter. It read:

Zmerr,

Come see me tomorrow, at your earliest convenience. I will be in my sanctum. I wish to properly reward your services. We shall discuss this more in person. Also, if you are interested in courting my daughter, you may, but you must respect her wishes. Much as I know how you met her, I will know how things are going between the two of you. Best not to ask how I know. Magic is a very useful tool. 

Signed,

Cadmus.