Let \( x_0 \) be the real number such that \( e^{x_0} + x_0 = 0 \). For a given real number \( \alpha \), define
\( g(x) = \dfrac{3x e^{x} + 3x - \alpha e^{x} - \alpha x}{3(e^{x} + 1)} \) for all real numbers \( x \).
Then which one of the following statements is TRUE?