This property controls whether an End Point Operations Management agent issues a warning when the vRealize Operations Manager server presents an SSL certificate that is not in the agent's keystore, and is either self-signed or signed by a different certificate authority than the one that signed the agent's SSL certificate.

When the default is used, the agent issues the warning
The authenticity of host 'localhost' can't be established.
Are you sure you want to continue connecting? [default=no]: 
If you respond yes, the agent imports the server's certificate and will continue to trust the certificate from this point on.