Do your research before meeting with this organization. How much do you know about the opportunity? The interviewer wants to know if this volunteer role will meet your needs, as well as theirs. You can also ask questions if there is anything you're not clear about.
"I expect that I'll be working with elderly, taking them for walks and assisting them on outings. I'm looking forward to working with others who are passionate about helping the elderly. Are there any other major proponents of this role that you would like to share?"
Entry Level answer example
"I expect to make a difference in the community and come across meaningful experiences with fellow volunteers or those we are giving to. I also expect to put in hard work, and I am excited to do so!"
Experienced answer example
"I am here because I would like to have an experience where my skills can help those who need it. I want to be pulled out of the bubble that my life has become, and understand what it takes to sacrifice for others."