or,she wants her to let down her guard and trust for easier brainwashing
Roxy, her new mother, was very attentive. She tried her best to relate to and aid Lily in whatever she could in order to get her to settle down quicker.
The reason why Harry managed to get a lake like liquid energy is because of his curse about being born with an adult mind, this was what made him happy, as it meant he was for the first time lucky.