Malicious Violet vs Fairy Pink

How close are they?

ΔE 18.3, loose: different enough that you should pick on purpose. Fairy Pink is a little lighter, much more saturated than Malicious Violet.

Can I use Fairy Pink instead of Malicious Violet?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Fairy Pink is a little lighter, much more saturated than Malicious Violet.

Can I use Malicious Violet instead of Fairy Pink?

The same difference applies the other way round: Malicious Violet is a little darker, much more muted.

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.