ΔE 22.0, loose: different enough that you should pick on purpose. Green is much more saturated, warmer than Majestic Fortress.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 22). Green is much more saturated, warmer than Majestic Fortress.
The same difference applies the other way round: Majestic Fortress is much 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 Majestic Fortress on the colour wheel See Green on the colour wheel
All matches: Majestic Fortress equivalents · Green equivalents