When the network has accepted your block and reached a consensus on it, the block is finalized
Use this command to check if a block with the given blockhash is finalized
rnode is-finalized <blockhash>
Here is an example of the console output following the is-finalized call.
$ rnode is-finalized f893a2ef3c9d69a0d8b2a660453abe0002628769c51f11af4d720e56c43a96d7 Block is finalized