There is rarely one right answer. Here are several categories of pairing options, each with a reason it may work.
Orchid
Similar lightness for a subtle, tone-on-tone pairing with minimal contrast.
Amethyst
Similar lightness for a subtle, tone-on-tone pairing with minimal contrast.
Magenta
Similar lightness for a subtle, tone-on-tone pairing with minimal contrast.
Mulberry
Similar lightness for a subtle, tone-on-tone pairing with minimal contrast.
Violet
Enough lightness contrast to read as two distinct colours without feeling harsh.
Hot Pink
Enough lightness contrast to read as two distinct colours without feeling harsh.
Plum
Enough lightness contrast to read as two distinct colours without feeling harsh.
Lilac
Enough lightness contrast to read as two distinct colours without feeling harsh.
Taupe Grey
A low-chroma neutral lets the original colour stay the visual focus.
Grey
A low-chroma neutral lets the original colour stay the visual focus.
Silver
A low-chroma neutral lets the original colour stay the visual focus.
Ash Grey
A low-chroma neutral lets the original colour stay the visual focus.
Lime
A saturated accent from a different hue family for a deliberate pop of contrast.
Chartreuse
A saturated accent from a different hue family for a deliberate pop of contrast.
Lime Green
A saturated accent from a different hue family for a deliberate pop of contrast.
Yellow
A saturated accent from a different hue family for a deliberate pop of contrast.