Is it ensure, insure, or assure?
mid-18c., lively Spanish dance, the word of unknown etymology [OED says "alleged to be of negro origin"], perhaps related to fado. Fado is lovely, but not lively, so perhaps the link, if any, is thematic. But the late date argues against it.
exuberant Spanish courtship dance and a genre of Spanish folk song. The dance, probably of Moorish origin, was popular in Europe in the 18th century and survives in the 20th century as a folk dance in Spain, Portugal, southern France, and Latin America. Usually danced by couples, it begins slowly, with the rhythm marked by castanets, clapping of hands, snapping of fingers, and the stamping of feet; the speed gradually increases. The music is in 34 or 68 time. Occasionally there is a sudden pause in the music, and the dancers stand rigid until the music resumes. The dance is an expression of passion, and the partners tease, challenge, and pursue each other with steps and gestures. In another version, the fandango is danced by two men as a contest of skill. The first dancer sets the rhythm and steps, the second picks up the step and elaborates.