https://phys.org/news/2018-05-remorse-wronged.html

It can be very hard to tell whether remorse is genuine or simply self-serving, expressed just in the hope of a lighter punishment. Sincerity can be hard enough to assess in our ordinary exchanges, but in the formal processes of criminal justice it is especially difficult.

While most of us think we can tell when remorse is genuine, there is little evidence that we can evaluate remorse accurately on the basis of facial expressions or other non-verbal indications. Such judgements are vulnerable to emotional, cultural and social biases. And at court, remorse is articulated not by the offender in person, but by their legal advocate, usually in carefully wrought, familiar, often over-polished expressions. Nor is an apology generally made directly to the victim, who may not even be present.