In the last ten years cloud computing has developed from a buzz word to the new computing paradigm on a global scale. Computing power or storage capacity can be bought and consumed flexibly and on-demand, which opens up new opportunities for cost-saving and data processing. However, it also goes with security concerns as it represents a form of IT outsourcing. We investigate how these concerns manifest as a decisive factor in cloud provider selection by interviews with eight practitioners from German companies. As only a moderate interest is discovered, it is further examined why this is the case. Additionally, we compared the results from a systematic literature survey on cloud security assurance to cloud customers' verification of their providers' security measures. This paper provides a qualitative in-depth examination of companies' attitudes towards security in the cloud. The results of the analysed sample show that security is not necessarily decisive in cloud provider selection. Nevertheless, providers are required to guarantee security and comply. Traditional forms of assurance techniques play a role in assessing cloud providers and verifying their security measures. Moreover, compliance is identified as a strong driver to pursue security and assurance.