I guess this is one of those instances where experiences somewhere else has changed a person so much that they might not really fit into their old life anymore. Maybe she figured that she can't tell her family the whole truth of what happened to her if she decided to return home (would anyone believe it?) and thought living with herself so changed while not being able to share so much of herself with them would be painful in a way too. Meanwhile she has build up new connections with a new family and friends and her lover who she shared everything with, who accepts her and who knows about her past and what happened to her (and knows she even killed someone).
Of course that doesn't make the choice easier, and she said she could regret this in the future but she made her choice now.
Plus she might not trust what the goddess might do anyway.