sure·ness 
/ˈʃɚnəs, Brit ˈʃɔ:nəs/ noun
/ˈʃɚnəs, Brit ˈʃɔ:nəs/ noun : a feeling that you know what you want to do and that you are able to do it [singular] ▪ He spoke with a newfound sureness [=confidence] in his voice. [noncount] ▪ She performs with the sureness of a veteran actress. ▪ the artist's sureness of touch/technique/hand
