Outbox v. Sentbox

[Parasurama]

What's the difference between the outbox and sentbox in private messaging? Is it that messages in the outbox haven't been sent yet? Or is it that messages in the outbox haven't been read by the person who they were sent to? Or is it something completely different? Basically I'm wondering if messages in the outbox have actually been sent.

[badgers]

outbox have been sent bt havent been read

[Parasurama]

Thank you sir