Bihar Chief Minister Nitish Kumar, who, following days of simmering tensions, finally ended his party Janata Dal (United)'s alliance with the Bharatiya Janata Party (BJP) and formed a government with the Rashtriya Janata Dal (RJD) and other parties earlier this month, has proved his majority in the state Assembly today with the 'Mahagathbandhan' comfortably winning the motion of confidence by voice vote amid a walkout by BJP MLAs.