Can someone explain the true namer class, especially when they speak an utterance do they have to make a Truespeak check, and what exactly is a reversal, and how do they do that
Utterrances are specific phrases that bring about a specific things. A Reverseal is the reverse meaning of the word. Almost any Utterance has one. However, they count as the same word for Law of Resistance.
My reading is that they don't count as the same for the Law of Resistance, as the Law of Sequence specifically states that a reverse and the normal count as the same for the law of sequence, and there's no such statement on the law of Resistance.
But it is still the same Utterance. But I guess that isn't explicit so maybe they count different.
I remember a few years ago seeing the Truenamer class as I browed Tome of Magic: Pact, Shadow, and TrueName Magic in the book store. I liked the flavor of the class so much, I bought the book. It's a really interesting concept.
Unfortunately, it was my experience that it kind of fell apart mechanically. The class felt broken.
The way I remember it was that as you got higher and higher level, it became increasingly more difficult to give buffs to yourself and your allies, let alone your enemies. To do so would require obtaining a good number of bonuses to keep doing the simplest thing. In some ways, it felt weaker as you leveled up.
I eventually gave up in frustration.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.