ΔE 29.6, loose: different enough that you should pick on purpose. Dechala Lilac is noticeably lighter, more muted, warmer than Purple Rain.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 30). Dechala Lilac is noticeably lighter, more muted, warmer than Purple Rain.
The same difference applies the other way round: Purple Rain is noticeably darker, 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 Purple Rain on the colour wheel See Dechala Lilac on the colour wheel
All matches: Purple Rain equivalents · Dechala Lilac equivalents