What made Nin begin to doubt Mansfield's mental stability in the memoir, Henry and June: From a Journal of Love: The Unexpurgated Diary of Anais Nin, 1931-1932?

According to Nin, Mansfield seemed incapable of reciprocating any sort of affection or love that went beyond a mere physical attraction. When she finally left and Nin was able to sort through her feelings, she realized that Mansfield was never able to speak plainly or honestly about anything in her life. In fact, nothing Mansfield ever said could give anyone any ideas about the woman herself.