The V officially stands for nothing. According to Fox, in 2010, she petitioned to have her name changed from Maria Vanessa Perez to V. Stiviano. Her stated reason in the court filing was, "Born from a rape case and having yet been fully accepted because of my race." She is of black and Mexican descent.
She looks like she’s of donkey and dog descent.
By way of fair warning and more brevity, maybe she could shorten it from V-Dot to V-D.