切切实实 is a four-character reduplicative idiom meaning 'thoroughly, genuinely, in a down-to-earth manner'. It emphasizes doing something in a solid, concrete, and uncompromising way — not superficially or half-heartedly. You'll often see it before verbs like 做到 (to achieve) or 落实 (to implement) to stress that the action is carried out fully and reliably.