When all is connected and the transaction is happening, the network behaves in an autonomous way. This is network reality. In other contexts, not using open source software, trust is established in different ways.
Trust in transactions in the network reality depends on the following elements: the steering of actions from one’s own machine; using publicly audited reputation (like open source); open communication; specific encryption for transaction; a network of independent actors; transactions only use a limited amount of time. However, there are many intermediaries (ISP, local installer, gateways etc.). Trust negotiation happens all the way to the last mile to the home.
Human beings give trust to systems and base their trust on systems as well. This can be false. A lot of trust is based on ignorance and perception instead of on reality and analysis. Trust is a hugely important question, no simple answers like more databases etc. There are a lot of irrational components to the design of trust.
And when already we left the building Sunil added: the best way to establish trust is by smiling and making people laugh….