ΔE 9.9, close: similar, with a visible difference side by side. Crimson Magenta is a little darker, warmer than Romeo/Juliet.
Usually, if you are not matching paint already on the model. Close match (ΔE 10). Crimson Magenta is a little darker, warmer than Romeo/Juliet.
The same difference applies the other way round: Romeo/Juliet is a little lighter, 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 Romeo/Juliet on the colour wheel See Crimson Magenta on the colour wheel
All matches: Romeo/Juliet equivalents · Crimson Magenta equivalents