Network slicing is key in guaranteeing verifiable or assured SLA at an application or at an end-user level, which is essential for monetizing new 5G services and new business models. Network slicing must be end-to-end, cutting across radio, transport, core and eventually across public clouds. To deliver network slicing at scale, service providers need to manage the complexity of orchestration, automation, and service assurance of these network slices across multiple domains, multiple clouds, multiple tenants, and multi-vendor ecosystems. Considering the E2E slice orchestration and assurance on O-RAN compliant 5G networks using Service Management and Orchestration (SMO), RAN Intelligent Controller (RIC) and RAN Slice SLA Assurance rApps and xApps.