Believe them the first time

When people show you who they are, Don’t treat them like who they should be.
Believe what they showed you the first time. Unless you’re in a situation where that person hasn’t been made aware of the consequences of their actions. Mercy can kill if distributed inaccurately. Mercy should only be extended to a broken heart. Someone willing to change. Evolve and adapt, extending mercy carelessly can lead to resentment.
You can measure people’s deserving of mercy by the degree to which they are adaptable. Forgive. Feed your enemy if they need food, but protect your atmosphere. It’s responsible to have boundaries.