1 level dip in Exemplar would suffice. +4 to Truespeak checks, and choose it as your Skill Mastery, and you can now take 10 on it.
The Skill Mastery point has already been covered, but the Skill Artistry bonus also won't work. It's a competence bonus, and hence won't stack with the OP's custom ring. Nor, for that matter, with the +4 a Truenamer gets for speaking his own personal name.

My biggest beef with the class is that a class really should be viable with the basic resources available to it. You ought to be able to make a decent Truenamer with human as your race, the elite array of ability scores, and no books other than PHB and ToM. Within those constraints, at level 1, you'll have a Truespeak check of +10 or +12 (+3 Int, +3 Skill Focus, +4 ranks; another +2 for targeting yourself) versus a DC of 17, and at level 20, you'll have a check of +48 or +50 (+11 Int, +3 Skill Focus, +10 amulet, +23 ranks, +1 Luckstone; another +2 for yourself) versus a DC of 55.

I'm a teacher. When I'm grading a test, if a student bombs absolutely everything else, I'll still give him a point or two for getting his name right. An out-of-the-box Truenamer can't even manage that, 20% of the time. That's pathetic.