Answer:
Prestige
Step-by-step explanation:
Prestige works best as an antonym because stigma relates to corruption, a stain of dishonor, etc.
Blight is more of a synonym, as a definition of stigma is tainted honor.
Logic doesn't necessarily work, as the word itself doesn't correlate specifically with stigma (as far as I know.)
Remorse doesn't really work as well, as having a stigma isn't the opposite of feeling remorse.