ΔE 15.3, loose: different enough that you should pick on purpose. Sap Green is more saturated, warmer than Guardian Green.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Sap Green is more saturated, warmer than Guardian Green.
The same difference applies the other way round: Guardian Green is more muted, 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 Guardian Green on the colour wheel See Sap Green on the colour wheel
All matches: Guardian Green equivalents · Sap Green equivalents