Directors in general, and community theatre directors in particular, tend to be people who are being tugged in several different directions simultaneously. So many projects they want to work on, so many ideas of how to do it, so many people they'd like to take part...
As such, verbal assurances from directors should be taken as compliments and precious little else. Even if they promise you a gig, they might just plain forget who you are by the beginning of rehearsals, or might meet someone they'd prefer, or their vision for the project might change in a way that would lessen your ability to contribute, or one of their "core" SMs might come available in which case they have no need for an outsider, or almost anything else.
When you get a contact, mark it on your calendar.
Until you do, don't count on anything.
I'm sorry you had this experience, though. It's a sucky lesson to learn, particularly when you're on friendly terms with the director in question.