Script not loading when depending on jQuery

You could run a couple checks and enqueue jquery if it’s not registered or enqueued using wp_script_is

function bootstrap_script_init() {

    // Check to see if jQuery is registered, if not, register it.
    // You can use the local version of WP's jQuery if you want instead of Google's API.
    if ( !wp_script_is( 'jquery', 'registered' ) ){
        wp_register_script( 'jquery', '//ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js', array(), '3.2.1', true );
    }

    // Check to see if it is enqueued, if not, enqueue it.
    if ( !wp_script_is( 'jquery', 'enqueued' ) ){
        wp_enqueue_script( 'jquery' );
    }

    wp_register_script('bootstrap', get_template_directory_uri(). '/js/bootstrap.min.js', array('jquery'), '3.3.7', true);
    wp_enqueue_script('bootstrap');
}
add_action( 'wp_enqueue_scripts', 'bootstrap_script_init' );