It isn’t that I don’t trust you or your intentions now, it’s that intentions (and requirements) change.
You asked about allaying fears. Personally for me this means actually take-to-the-bank licensing that I could get through a legal audit, even if hypothetical.
Talk of “secret sauce” and future closed source and IP licensing of future maybe-must-have magic... that’s way too much future risk for me.
An example of what I think is good licensing is JUCE (https://juce.com). Everything from “free” to “paid with support”, all open source… but the point is I always know exactly where I stand legally, what I can and cannot do... and what I can and cannot do in the FUTURE.