BASH script to handle “authentication realm”

Question

I have multiple SVN repositories which I intend to synchronize with other SVN server each night using svnsync like this:

svnsync synchronize --source-username my_server_user_name --source-password ... --sync-username dest_server_user_name --sync-password ... svn://dest_svn_server/svn/[repository_name]

But it fails with "Authentication realm" error and asks to enter login-password - when I enter dest_server_user_name-password again - it succeeds.

Is there a way to do it automatically somehow?

Thank you.