I have received several personal letters from editors rejecting (in a very nice way) my submission. In one case, the editor wrote me a personal rejection letter twice though I told him not to feel the need to respond to the revision if he wasn't interested. His last letter read in part as follows:
“Thank you for sending me the revised manuscript…. I do think the manuscript is much stronger. The central storyline is clearer and the characters are more defined. But I’m sorry to say that I still don’t feel that the story is distinct enough for the marketplace. It may be that another editor will respond more positively, and I would be happy if that were so.”
Do you think this editor thinks my manuscript has potential or is he just a nice guy? I've read several things that would suggest this type of rejection indicates he has an interest in my work, but I’m not convinced. I don’t mind revision or re-submissions, I just don’t want to be a pest to this guy when he’s been nice enough to personally respond. What insights can you provide?
This editor thinks you have potential, but he's done with this manuscript. And he's a nice guy. If, after I reject something, I don't specifically invite a resubmission, I'm letting the thing go. And suggesting that other editors/publishers may respond more positively is always code for "I'm washing my hands of this".
But sending you a letter with specific, constructive criticism (in this case, "your hook isn't sharp enough")—is a real sign that he thinks you've got something. Send him whatever you next write.