Use the following line (in /etc/sudoers) to sudo without having the system to prompt without password.
# User privilege with no password varun.verma ALL=NOPASSWD:ALL
When multiple entries match for a user, they are applied in order. Where there are multiple matches, the last match is used (which is not necessarily the most specific match). Therefore, it is important that this statement must be the last line of the file or beyond the group permission.