Why did Sai Baba say he couldn't give a mantra to the woman who asked for one?

In Chapter 19, Sai Baba explains to a woman that he cannot give her a secret mantra, or 'upadesh,' because his own Guru never gave one to him. Baba recounts that despite serving his master for twelve years with a strong desire for a mantra, he never received one through verbal instruction. Instead, his Guru provided spiritual nourishment and protection through his powerful gaze, much like a mother tortoise feeds her young from afar. Baba directly tells the woman, 'my Guru did not blow any mantra into my ears, so how can I blow one into yours?' He advised her instead to simply 'pay attention' to him, suggesting that this focused devotion is the true path to spiritual wealth.