You want me to pull apart you analysis? you asked for it! LOL!
(1) First of all you bring in a wrong assumption, that there are "real Christians" and I guess not real Christians -- Sorry, there are only Christians and non-Christians
(2) The verse says absolutely nothing about repenting or not repenting of the sinning.
(3) And actually, it does not anything about sinning "willfully" - sinning continuously and sinning willfully are not the same thing
(4) And the verse says nothing about the Spirit convicting of the sin (Now of course this might happen but that is not what the verse says!)
I have nothing against what you say - it is probably pretty true, but it is not a correct exegetical meaning of the verse.