ΔE 33.2, loose: different enough that you should pick on purpose. Witch Purple is noticeably lighter, more saturated, cooler than Quinacridone Magenta.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 33). Witch Purple is noticeably lighter, more saturated, cooler than Quinacridone Magenta.
The same difference applies the other way round: Quinacridone Magenta is noticeably darker, more muted, warmer.
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 Quinacridone Magenta on the colour wheel See Witch Purple on the colour wheel
All matches: Quinacridone Magenta equivalents · Witch Purple equivalents