What's the story behind Appasaheb's promise to give ten rupees and why did he hesitate when a Fakir appeared?

The story from Chapter 33 recounts that after his family gave only one Rupee, Appasaheb Kulkarṇi felt it was an insufficient offering. He mentally resolved, "Had I been there, I would have given ten times more," thereby giving his word to offer ten Rupees. To become free from this self-imposed debt, the promise had to be fulfilled. Later, a Fakir, implied to be Sai Baba in disguise, came to him. However, because this Fakir was a stranger, Appasaheb became suspicious. Despite having six Rupees available at that moment, his hesitation and doubt caused him to not make the offering at that time.