What's the full story behind Appasaheb's promise to give ten rupees? Why was he suspicious of the Fakir who came to collect it?

The story of Appasaheb's promise is detailed in Chapter 33. Appasaheb felt that the single Rupee his family had given to a Fakir was insufficient and mentally resolved that he would have given ten Rupees. The narrative explains that to fulfill this promise and become free from the 'debt' of his word, the full amount had to be given. Sometime later, a Fakir, who was actually Sai Baba in disguise, came to him. However, as Chapter 33 notes, because this Fakir was a stranger to him, Appasaheb became suspicious. His hesitation and doubt prevented him from making the offering at that moment, even though he had six Rupees available. This story illustrates the human tendency to falter even when an opportunity to fulfill a good intention presents itself.