I'm not sure it's the passage you're thinking of, but I did find a passage along similar lines about a quarter of the way down this webpage:
http://www.byronevents.net/nisargadatta/that9.htm
The passage begins: 'Q: Sir, I am an humble seeker, wandering from Guru to Guru in search of release.' (I found the passage by searching the webpage for the word 'despair', by pressing CTRL+F and then entering the word in the box that comes up.)