Above all, you’ll be free of fear and desire. And how long your body will contain the soul that inhabits it will cause you not a moment’s worry.
(Meditations by Marcus Aurelius, translated by Gregory Hays.)
It's clear that the author here implies that he is not at all going to worry about his lifespan. However, I wonder whether the phrase not a moment’s worry may convey the opposite meaning in a different context.
For example, can I desperately utter something like These new dreaded taxes will cause me not a moment's worry meaning I will be staying in a state of anxiety for a time period much more longer than "a moment" or the only possible understanding is that of "I could care less over those taxes"?