This paper aims to identify the importance of security at the SLA level (Service Level Agreement), given the low utilization of Cloud Computing services at the economy level. The article presents in the first part the deficiencies in the adoption of cloud services, presenting at statistical level the degree of adoption by countries and branches of activity. In the second part, we present the concept of SLA (the document that governs the client-provider cloud computing relationship) as well as the most important criteria for the development of an SLA. In order to provide services with a high degree of trust, the most important metrics regarding security assurance are presented at the SLA level. Finally, in order to increase trust in cloud services, a set of metrics can be proposed that can be included in SLA documents (Availability and maintenance time, list of services and resources that are provided by the provider to the clients, application response, advance notification program of network changes that may affect users, support desk response time for different problem categories, consequences in case of breach of agreement).