How to change title “Search Results for:….” in search results page of genesis?

Use the 'genesis_search_title_text' filter:

add_filter( 'genesis_search_title_text', 'wpse_101947_search_title_text' );

function wpse_101947_search_title_text() {
    return 'Translated text';
}

Replace Translated text with your translated text.