The term "white" is often associated with light or pale skin tones, so if you're asking which hair color can make a girl with fair skin appear even paler or more porcelain-like, here are some suggestions:

1. Platinum Blonde: A bright, cool-toned platinum blonde can create a stark contrast against fair skin, enhancing its paleness. This ultra-light shade can give the illusion of a more translucent, "white" appearance. However, achieving and maintaining a true platinum blonde may require extensive bleaching, which can be damaging to the hair.

2. Icy Blonde: Similar to platinum blonde, an icy blonde hue features cool, silvery tones that can accentuate the fairness of a girl's skin. This shade is often created using toners or glosses containing blue or violet pigments to neutralize any yellow or warm undertones, resulting in a more "white" appearance.

3. Ashy or Silver Grey: A cool-toned ash grey or silver hair color can complement fair skin by creating a monochromatic, ethereal look. The cool, muted tones can enhance the paleness of the skin, giving it a subtle "white" appearance. This color is particularly striking when paired with minimal makeup and light-colored clothing.

4. Pastel Tints: Soft pastel shades like baby pink, lilac, or light blue can add a delicate, whimsical touch to fair skin, giving it a subtle "whitewashed" appearance. These colors work best on pre-lightened hair and may require regular touch-ups to maintain their vibrancy.

5. Nude or Neutral Browns: If you prefer a subtler approach, nude or neutral brown shades with cool or ashy undertones can create a soft, understated look that enhances the fairness of your skin. These colors can make the skin appear more luminous and "white," without the high contrast of lighter shades.

It's essential to consider your skin's undertones (cool, warm, or neutral), eye color, and personal style when choosing a hair color to enhance the "whiteness" of your skin. Additionally, keep in mind that hair color can interact differently with various skin tones, so it's always a good idea to consult with a professional hairstylist for personalized advice and a color consultation.