Bethany was born along with her twin brother, Lancel, to Lord Barristan and Lady Jocelyn two years after her elder brother, Jon. From a young age she favored books and learning, much like her father, and learned to read earlier than any of her siblings.
She was trained and tutored by her lady mother, her septa and by her uncle's wife in the usual education a lord's daughter would receive, as well as by her father in histories, mathematics and sailing.
After the Ascent of the Lion her twin brother was sent to Storm's End to be a ward and hostage, but died in the crossing when he fell overboard and drowned. She became a quiet and withdrawn girl for many years following his death.
Her family attended the Tourney of Blackhaven, and was introduced to Lord Dondarrion's second son, Maldon. She became infatuated with the scholarly young man, and aided in his recovery after being injured as a mystery knight who wore her favor. After her return to Rain House began writing to him almost daily. With the rise of rebellion against the Conningtons, her father betrothed her to Maldon Dondarrion to secure their alliance.
She departed Rain House with her family and betrothed after the sacking of Oniontown, to the safety of Blackhaven.