How did Sai Baba prove to his devotee, Dev, that he keeps his promises, even when it seems like he hasn't?

In a remarkable incident from Chapter 40, a devotee named Dev felt disappointed and deceived when Sai Baba didn't appear to attend his Udyapan ceremony as promised. Dev wrote a letter to Jog expressing his confusion. When Jog presented this to Baba, Sai revealed the truth of the matter. Baba explained that he had indeed attended the feast, but in the guise of a Sanyasi, accompanied by two other people, just as he had said he would. Baba stated, "The words from My mouth shall never be otherwise." This revelation, communicated back to Dev, caused Dev's eyes to overflow with love, making him realize he had blamed Sai in vain and profoundly reinforcing his faith in Baba's word.