Arriving in pursuit of her daughter , Lady Bracknell is astonished to be told that Algernon and Cecily are engaged . The revelation of Cecily 's trust fund soon dispel Lady Bracknell 's initial doubts over the young lady 's suitability , but any engagement is forbidden by her guardian Jack : he will consent only if Lady Bracknell agree to his own union with Gwendolen — something she decline to do .