ΔE 29.2, loose: different enough that you should pick on purpose. Dead Flush is a little darker, much more muted, warmer than Fey Pink.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 29). Dead Flush is a little darker, much more muted, warmer than Fey Pink.
The same difference applies the other way round: Fey Pink is a little 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 Fey Pink on the colour wheel See Dead Flush on the colour wheel
All matches: Fey Pink equivalents · Dead Flush equivalents