his fault
He said it was his fault.
This wasn't his/her fault.
He told me it was his fault.
Non è stata colpa sua se ha scelto lui.
It wasn't her fault she chose him.
— Ирония судьбы, или С легким паром! (1976)
I don't think it's his fault.
Mi ha detto che era colpa sua.
He told me it was his fault.
He admitted it was his fault.
Tutti sanno che non era colpa sua.
Everyone knows it wasn't his fault.
Non pensa che fosse colpa sua.
He/She doesn’t think it was his/her fault.