Confidence in eCommerce is a big issue and seals or certificates from respected institutions help to gain visitor's trust in online shops much better than without them and it gets the visitors to spend more money.
One of those trusted body's in Germany is TrustedShop. They have analyzed and approved several thousand online shops so far and granted their highly regarded certificates.
Online shop customers do have the choice after completing an order in a TrustedShop-certified onlie-shop to sign up for an insurance for that order with full money back guarantee.
This module (uc_trustedshops) integrates full functionality of the TruestedShop range of services including the display of the certificate in a block as well as integration into the orderprocess from Ubercart to allow customers to select the insurance.
More details about TrustedShops can be found on their website (http://www.trustedshops.com).