Nec habeo nec careo nec curo.
(Motto)

pron = neck hah-BAY-oh neck kah-RAY-oh neck KOO-roh

I do not have; I do not lack; I do not care.

Comment: I have translated this proverb very (if not too) literally. So, let's look at what these words can also mean.

I do not have (anything) can also mean that I don't hold onto anything. I don't cling. I am not attached. I don't possess things such that things possess me.

I don't lack anything BECAUSE I don't cling to things. I can let things go without anxiety because I don't cling to them.

I don't care can also mean that I don't worry. I am not anxious.
Anxiety comes when I feel that I am being depleted. So, a looser but perhaps more revealing translation might be:

I don't cling to anything, and so, I don't really feel the loss of anything, therefore, I am not worried.

And, we could turn these into questions:

What things do I think I have? Do they really have me?
What is it that I believe I lack? If I had them, would my life be complete?
What do I worry about? Why?