source_of_the_sovereign/src/moves/assurance/assurance.c

#include <battle_locations.h>
#include <battle_structs.h>

void assurance_damage_modifier()
{
    if((battle_protect[battle_defender_bank].physical_damage + battle_protect[battle_defender_bank].special_damage) > 0)
        battle_damage_multiplier *=2;
}