Apparently, thusly:
IF
Action = evil
AND
motive = evil
THEN
Evil alignment.
IF
Action = evil
AND
motive = neutral
THEN
Evil alignment.
IF
Action = evil
AND
motive = good
THEN
?!!?!!?!!
IF
Action = neutral
AND
motive = evil
THEN
Evil alignment.
IF
Action = neutral
AND
motive = neutral
THEN
Neutral alignment.
IF
Actin = neutral
AND
Motive = good
THEN
Good alignment.
IF
Action = good
AND
Motive = evil
THEN
Evil alignment.
IF
Action = good
AND
Motive = neutral
THEN
Neutral alignment.
IF
Action = good
AND
Motive = good
THEN
Good alignment.
I believe this is true, but I am not positive without looking it up in the PHB and DMG.