To be sure or certain about something.
सुनिश्चित होना
English Usage: She knows for sure that he will come.
Hindi Usage: उसे निश्चित है कि वह आएगा।
nishchit hona, nishchit honaa, nishit hona, nishchit ho jaana, nishchit honaa hai, nishchit hona chahiye