Why Chris Harrison Says 'Bachelorette' Hannah Brown Might Not Get a Happy Ending This Season (Exclusive)

The longtime host also admits he was 'scared to death' Hannah might not be the right choice.

Hannah Brown's season of The Bachelorette might actually be the most dramatic one ever.

Colton Underwood's Bachelor season was the first in five years not to end in a proposal, and according to host Chris Harrison, Brown's could be the first in Bachelorette history not to conclude with a man down on one knee.

"I wish I could guarantee [a proposal], but I cannot deliver…  I don't know, I would love to be able to do my job and deliver this, but I don't know if we're going to," Harrison told ET's Lauren Zima during a sit-down interview last week. "It might be a bumpy finish."

Aside from Underwood, Harrison admitted that usually at this point in a season (Brown was just heading into her finale), it's "smooth sailing."

"Sitting here now, I really don't know how it's going to end. I am hopeful and she is hopeful, but the way she wants to find love and the way she is going about this is really true and sincere. She is not just going to do it to do it, and as rough as it has been and as wild as it has been, I am not sure she is going to be able to get there. And that is because she doesn't know if she will be able to get there," he explained. "So, I am interested as anybody to see how this all wraps up."

Harrison, who admitted he was "scared to death" that Brown might not be able to handle her Bachelorette duties after her rocky debut on Underwood's After the Final Rose, said that "man drama" on night one forced Hannah "Beast" to come out a little early. However, it doesn't sound like she was ever able to nip the drama in the bud.

"She came in as the Bachelorette just firing on all cylinders and took control," Harrison said. "There was an incident on night one -- I'll say thanks to Demi [Burnett] and Katie Morton [who were in a surveillance van for the premiere] that I thought, 'OK, this might be where I step in because Hannah is not really ready for this yet.' She looked and said, 'I got this.'"

The longtime host teased that while an ambulance isn't involved in the night one spectacle, it comes into play later in the season. Fans can expect both tears and fist fights, he said.

"There is a guy not there for the right reasons, then there are the guys that just rub everyone the wrong way, that everyone loves to hate. It's just stuff she has to deal with constantly, and every time we think we're over it, it rears its ugly head and she has to get back in," Harrison revealed. "It really got to the point where honestly, it started taking away from her being the Bachelorette. It took away from the entire season and the chance for her to find love, and it may cause her not to find love at the end of this."

And while Brown won't have a fence jump moment like Underwood did, Harrison said things will come to a climax in terms of the drama with Hannah's men. "You are going to see drama along the way, let's say it's a level two drama. This is a level 10 drama that really festers and really dives into the fabric of the show. I think it's going to shape this entire show, because it has to do with somebody she really cares about, and so it's not something that is just going to go away."

Part of the problem was that the men just wouldn't accept each rose ceremony as a "clean slate," he added. "It's kind of like this snowball effect," Harrison reasoned, though was quick to note the drama didn't necessarily escalate because Brown didn't send home guys she should have. "Hannah gets to see what she gets to see and that's it. [Aside from the surveillance van in the premiere] it's not like we sit back and show her tapes of everything else going on, so she only can judge from what she says and she likes what she sees."

As for which suitors of Brown's 30 men (three of the previously announced 33 didn't make the cut for the premiere) fans should keep an eye on this season, the host said there are a couple standouts.

"John Paul Jones, because I love saying John Paul Jones. And you have to use his full name… he refers to himself in the third person as John Paul Jones," Harrison joked.

"I would say keep an eye on Peter, he wears the [pilot] uniform, shows up on night one. Big Mike is just this adorable, endearing and lovable, lovable character. He's that guy in the house that everybody likes. But… is he friend zone material?" he teased. "Now let's go LA, Dylan. Because of who Hannah is -- family, down home, roots, loves that -- that is Dylan. He has an amazing story that he'll share and he's quiet and kind of is in the background. But not so much like, 'Who's that guy?' He's just that guy that's always there. And he shares this, he's kind of the mirror image of who Hannah is, and obviously that's a comfortable thing to see."

Brown's "badass" and "drama-filled" Bachelorette premiere airs Monday at 8 p.m. ET/PT on ABC. Join ET's Bachelor Nation Facebook group here.