You can tell the status of your Deputies, and whether they have accepted your request from the Deputy tab. For example, in the following picture, there are two deputies who have accepted the vaultbox request, and one that has not.

IMPORTANT - once your deputies have accepted your request, you must visit the Deputy tab once to automatically distribute the keys to unlock your vaultbox.  This has to be initiated from your side as the keys are encrypted using your secret encryption key, to which vaultbox does not have access.