ΔE 40.4, loose: different enough that you should pick on purpose. Amethyst Rose is noticeably darker, much more muted, warmer than Pink Horror.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 40). Amethyst Rose is noticeably darker, much more muted, warmer than Pink Horror.
The same difference applies the other way round: Pink Horror is noticeably lighter, much more saturated, cooler.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Pink Horror on the colour wheel See Amethyst Rose on the colour wheel
All matches: Pink Horror equivalents · Amethyst Rose equivalents