Lesbianism
I can't believe nobody is writing about this. Emanuel had sexual fantasies about her stepmother, suspicious and interesting attraction to Linda, not to mention this movie was written and directed by an open lesbian.
Wait, I know what you are going to say "She only missed a mother, she had a boyfriend" As Emanuel's stepmother said, her never having a mother created confusion with her not being able to distinguish mother's love and sexuality, Jessica Biel was only a few years older than her - more fited to be a lover than a mother. As for the boyfriend I feel she was using him to prove to herself and her family she likes men. Further his character was put there not to make her appear just anotehr lesbian which would make her attraction to Linda less interesting.
In short I think she really liked Claude but had bisexual tendencies for Linda combined with need for motherly love.