Created host with id 10047. Then used zbx-jsonrpc-api to delete host:

Request:
{"jsonrpc":"2.0","method":"host.delete","params":

{"hostid":10047}

,"id":0,"auth":"07fcc311577bba47b624a997a1042ca5"}

Response:
{"jsonrpc":"2.0","result":

{"hostids":[10047]}

,"id":0}

But the host won't be deleted, still exists.