WordPress at a glance
function is not described

reset_password() WP 2.5.0

Handles resetting the user's password.

Hooks in function
Return

Nothing (null).

Usage

reset_password( $user, $new_pass );
$user(WP_User) (required)
The user
$new_pass(string) (required)
New password for the user in plaintext

Code of reset password: wp-includes/user.php WP 5.2.1

<?php
function reset_password( $user, $new_pass ) {
	/**
	 * Fires before the user's password is reset.
	 *
	 * @since 1.5.0
	 *
	 * @param object $user     The user.
	 * @param string $new_pass New user password.
	 */
	do_action( 'password_reset', $user, $new_pass );

	wp_set_password( $new_pass, $user->ID );
	update_user_option( $user->ID, 'default_password_nag', false, true );

	/**
	 * Fires after the user's password is reset.
	 *
	 * @since 4.4.0
	 *
	 * @param WP_User $user     The user.
	 * @param string  $new_pass New user password.
	 */
	do_action( 'after_password_reset', $user, $new_pass );
}