This expression is not used everywhere in Brazil, and its meaning varies depending on the age group, and region of the person using it.
It can mean “honestly”, “sincerely”, “for real”, or it can be used as a form of asking for a favour. It is used informally.
- O que você acha dele?
Na moral? Odeio.
Ow faz isso aí pra mim, na moral?
- Na moral, tá chato isso. Para.