The secret about her half siblings was something Lady Felicia vowed to take her to her grave, no matter what happened or how much torture she was put through.
Hence mixed in with all the truths, Lady Felicia inserted this one lie.
And fortunately for her, Alexander did not seem too interested in the possibility in the first place.
For she and Lapitus proved adequate to rule the city and choosing an unknown, inexperienced, most likely illiterate man over them simply because of his birth seemed too big a hassle.
Thus as long as the couple were willing to be Alexander's darling puppets, he would let them rule the city.
Thus, not putting much thought into the answer, Alexander then turned to the last and most important query he had.
"You said, you doubted Lapitus's loyalty to me. Do you still believe that? Or was that a lie too?"