Why doesn't Cecily care that Algy's name isn't Earnest at the end of the book?

It seems that Cecily is impressed by Algernon's confession that he only pretended to be Jack's brother Earnest in order to gain an introduction to Jack's ward..... Cecily.

Cecily.  Gwendolen, your common sense is invaluable.  Mr. Moncrieff, kindly answer me the following question.  Why did you pretend to be my guardian’s brother?

Algernon.  In order that I might have an opportunity of meeting you.

Cecily.  [To Gwendolen.]  That certainly seems a satisfactory explanation, does it not?