ΔE 33.2, loose: different enough that you should pick on purpose. Pastel Violet is much more muted, cooler than Impish Rouge.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 33). Pastel Violet is much more muted, cooler than Impish Rouge.
The same difference applies the other way round: Impish Rouge is much more saturated, 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 Impish Rouge on the colour wheel See Pastel Violet on the colour wheel
All matches: Impish Rouge equivalents · Pastel Violet equivalents