"Omotenashi" is imagining what the other person wants and putting it into action. It is said to be a uniquely Japanese culture. Similar words include "service," "customer service manners," and "hospitality," but they are not exactly the same.
It is closely related to the Japanese temperament and culture of carefully observing and caring for others.
It is treating others with an honest heart.
The essence of "omotenashi" is always thinking about how to make people happy and satisfied, and putting that into action.