What is rebeccas explanation on the girls behavior?

In the context of _Daphne du Maurier’s novel “Rebecca,”_ Rebecca is not alive so cannot provide any explanations.

Are you perhaps referring to an adaptation of the story where we meet Rebecca's ghost, or Mrs Danvers (Rebbeca's housekeeper), who can often speak on Rebbeca's behalf due to an unhealthy, bordering on obsessive, loyalty?