add_shortcode( 'product_rating', 'bb_show_product_rating_based_on_id' );
function bb_show_product_rating_based_on_id( $atts ) {

    $atts = shortcode_atts( array(
        'id' => '',
    ), $atts, 'product_rating' );

    if ( isset($atts['id']) && $atts['id'] > 0 ):
    // get WC_Product Object
    $product = wc_get_product( $atts['id'] );

    // product average rating (how many stars the product has)
    $average = $product->get_average_rating();
    endif;

    if ( isset($average) ) :
    return wc_get_rating_html($average);
    endif;
}