Why is this with Patter.MULTILINE set not matching?

As far I understood Pattern.MULTILINE it should try to match every string separated by n.

    String str = "^.*is.*$";
    String txt = "this is mynvery simple text";
    
    Pattern pat = Pattern.compile (str, Pattern.MULTILINE);
    Matcher mat = pat.matcher (txt);
    
    System.out.println ("matches="+mat.matches ());  // -> false