Asked to sign pamphlets that committed them to Clinton as they walked into the event at Case Western Reserve University, voters said their hesitance stemmed from a mix of issues, including trustworthiness, the prospect of Vice President Joe Biden getting into the race and the fact that other Democrats, primarily Vermont Sen. Bernie Sanders, are running.
"I love her and admire her as a strong woman," said Jane Underwood, an undecided Ohio Democrat who voted for Obama in 2008 and 2012. "But I don't trust her. I am sad that I can't [endorse her] but I don't [trust her]."
Underwood, who came to the event to see what Clinton had to say, added, "I'd like to have a woman. That is what makes me sad. ... I wish that I was able to endorse her in a more strong way. But I can't."
That sentiment was not unique.
Mythili Ramakrishna, a dentist from Cleveland who attended the event with her husband, said that she came to the event undecided and left the same way. In particular, Ramakrishna said she has been concerned with Clinton's lack of specificity.
"She talks about raising minimum wage, but I'd love for her to say a number," said Ramakrishna. Clinton has backed raising the minimum wage to $10.10 and said she is interested in a proposal that would rise it to $12, but the candidate has specifically not backed a $15 minimum wage plan that other Democrats have supported.
"There is a lot of overview kind of statements that are being made, nothing specific, so that concerns me," Ramakrishna said.
Though there were plenty of solid Clinton supporters at the Ohio rally -- 2,800 people in total came to see the former secretary of state, according to the university -- it was strikingly easy to find Democrats who were skeptical.
Ohio has always been a stronghold for the Clinton family. Former President Bill Clinton won the state in 1992 and 1996, and Hillary Clinton convincingly won the state's primary in 2008.
On Thursday, Clinton said she would never forget what "Ohio did for me in 2008."
"You lifted me up when I was down and out," she said, referring to the state helping get her struggling campaign back on its feet temporarily.
Ohio looks like it is still fertile Clinton territory. A Quinnipiac poll released earlier this month showed Clinton had a sizable 30-point lead over Sanders.
But the state's primary is months away, and if the voters at Thursday's Clinton rally are any indication, the candidate will have to work to solidify her support in the Buckeye state.
"If she ends up with the Democratic nomination, I don't think I would hesitate to vote for her," said Anna Hirsch, a student from the Cleveland university. "But in terms of the primary itself, currently I am leaning towards Bernie Sanders."
She added, "I guess I like that he seems very much to be in touch with what the American people need. ... I think he stands for a lot and he has always been very clear about what his expectations are and what he plans to do."
In addition to Sanders, some Democrats said they were keeping an eye out for Biden, the sitting vice president who has been exploring a run behind the scenes.
"I think there is room in the race for another strong candidate and I think I would like to hear his voice," said Bernie Jim from South Euclid, Ohio. "I don't know if it would shake me from being a Hillary supporter but I could see him in the race."
Eva Katsaros, another student at Case Western, said she was "definitely" looking at Biden, primarily because his views "more align with what I think."
Not all attendees had eyes on Biden. Phyllis Leder, a 67-year-old Ohio voter, said she was feels like Clinton resonates with women and middle class voters like herself.
As for Biden, it isn't his time, she said.
"If I were his wife," Leder said with a smile, "I would tell him, 'Don't do it.'"