You require honesty from M because you are requiring honesty of yourself, to yourself.
M has clarification to do.
You are.
It is better to know.
Please remember what I said about our relationships changing as we change, and being what we needed when that was what we needed.
Nothing has to happen, right now.
I see in this that the sister cares for you. What I do not like is that when the sister came back, M implied you should wait for her to call you.
That is gaslighting.
Cedar