ΔE 13.7, fair: the same colour family, but not a straight swap. Trollslayer Orange is a little lighter, warmer than Rust.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Trollslayer Orange is a little lighter, warmer than Rust.
The same difference applies the other way round: Rust is a little darker, 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 Rust on the colour wheel See Trollslayer Orange on the colour wheel
All matches: Rust equivalents · Trollslayer Orange equivalents