Display the search results like the original pages

Question

I'm creating my site (locally) and I'm using the starter theme underscores.me

I created few pages using bold, italic, and other text styles, but I noticed that in the Search Results page, the content of the pages is displayed without the text styles.

Look at this image to better understand the problem:

I'm almost sure that in order to customize the search behaviour I have to edit the file searchform.php or search.php, but I don't know what I have to write in there.

Could you help?

Many thanks

EDIT

Here it is my search.php content:

<?php
/**
 * The template for displaying search results pages
 *
 * @link https://developer.wordpress.org/themes/basics/template-hierarchy/#search-result
 *
 * @package sitename
 */

get_header();
?>

    <section id="primary" class="content-area">
        <main id="main" class="site-main">

        <?php if ( have_posts() ) : ?>

            <header class="page-header">
                <h1 class="page-title">
                    <?php
                    /* translators: %s: search query. */
                    printf( esc_html__( 'Search Results for: %s', 'sitename' ), '<span>' . get_search_query() . '</span>' );
                    ?>
                </h1>
            </header><!-- .page-header -->

            <?php
            /* Start the Loop */
            while ( have_posts() ) :
                the_post();

                /**
                 * Run the loop for the search to output the results.
                 * If you want to overload this in a child theme then include a file
                 * called content-search.php and that will be used instead.
                 */
                get_template_part( 'template-parts/content', 'search' );

            endwhile;

            the_posts_navigation();

        else :

            get_template_part( 'template-parts/content', 'none' );

        endif;
        ?>

        </main><!-- #main -->
    </section><!-- #primary -->

<?php
get_sidebar();
get_footer();

Answer 1

Usually when search results pull a page's content into a section for an excerpt, it runs the content through a filter which runs strip_tags or some equivalent WordPress specific function that removes any and all HTML tags so as to not break the site due to a opening <div> tag not having a closing partner because the excerpt cut off the ending before it was properly closed, and would then potentially break the layout of the site, and other reasons, but that's the simplest example.

To customize the behavior, you will probably have to edit search.php or content-search.php (if it exists) to pull in your own version of the content to show, whether it be all the content, or a modified version of the excerpt system.