What is the ruling of Islamic law on the misuse of trust, what is the definition of betrayal, and what is the ruling on the betrayer in Islamic law?

The Shari'ah encourages safeguarding trusts and forbids their squandering. It commands their return to their rightful owners, as Allah Almighty says: "Indeed, Allah commands you to render trusts to whom they are due." Squandering a trust is a sin and a transgression against the commands of the Shari'ah. Treachery is the failure to advise the owner of a trust against its squandering and betraying them. Whoever commits an act of treachery is obliged to make sincere repentance by returning the right to its owner.