Returning the entire line of a custom search result filter

Well you can try to do while(have_posts()) – a standard query loop in your search page.
Than you can try to highlight (in example its marking a search occurance of the search string), but you can modify example and show only your search word occurance.

function sublinhamos($text, $words) {
    $wordsArray = array();
    $markedWords = array();
    // explode the phrase in words
    $wordsArray = explode(' ', $words); 

    foreach ($wordsArray as $k => $word) {
      $markedWords[$k]='<mark>'.$word.'</mark>';
    }

    $text = str_ireplace($wordsArray, $markedWords, $text);

    //right trows results
    return $text;
}

source of code