Who is Rambha from Gandhi, the Man and what is their importance?

Rambha was a family servant in Gandhi's house as a youth who taught him not to let fear take him, but to repeat the mantra for abiding joy: "Rama, rama, rama." She compared a mantra to the stick of bamboo that, when held in an elephant's trunk, keeps the elephant's trunk calm and still instead of waving and sniffing around the crowded city markets.