Dear Andy,
I have very much enjoyed being your pen pal, and I too was hoping to further our intimacy with an in-person meeting - but I'm not sure I can consent to do so any longer. Had I been aware that you were an alligator at the beginning of our correspondence I might not have allowed such intimacy to grow between us. You have such very pointy teeth you see, and I fear them.
Your friend and confidante,
Lorraine