Sure, they’re vain and stubborn.

Of course, they fight and bicker and call each other names.

But Beatrice and Benedick — the warring lovers in “Much Ado About Nothing,” opening tomorrow night at Hudson Valley Shakespeare Festival in Garrison — have a deeper, more complex relationship than do Hero and Claudio, the story’s more amiable pair.

So say Nance Williamson and Jason O’Connell, who play the more quarrelsome couple, in a production directed by Cold Spring’s John Christian Plummer. (Photo by Carucha Meuse/The Journal News)

“Before the play begins, Beatrice and Benedick have a past, something happened, hearts were broken and they have history with one another that is in full scrape,” Williamson says.

Adds O’Connell with a laugh: “You have to know someone really well to hate them that much.”

Hero and Claudio, the young lovers everyone’s rooting for (played by newlyweds Katie Hartke and Ryan Quinn), are a different story, says O’Connell.

“The truth is that they get engaged with all smiles and tears and laughter and joy without saying a word to each other,” he says. “That’s fine, but that’s love at first sight or just superficial, like when love strikes you’ll know it. It’s kind of storybook, and I get the impression that they might not know that much about each other.

“At the end of the play … I think this couple already knows what drives each other crazy, knows the other’s weaknesses and faults,” he says.

The journey from archrivals to the altar begins in earnest with the play’s most memorable moments.

They’re called “the gulling scenes,” when Beatrice and Benedick are being gulled by those who know them the best and love them most. Their friends make sure that the two lovers hear them talking about how much the other loves them.

“There’s a truth-telling in their lying,” Williamson says. “What they’re saying is not true, but there’s a kind of truthfulness in what’s being said even though the facts aren’t real. They’re saying (Beatrice and Benedick) are prideful, which is true. She is prideful, she is disdainful, she is all of those things. And when they say Benedick will die because he loves her so much, that hasn’t happened, but in truth, they should be together. There’s a love connection that’s not rooted in actual fact or truth, but the seeds are there.”

“If they didn’t already love each other,” O’Connell adds, “this wouldn’t do it. It would give them ammunition to use against the other. But these feelings live in them.”

Still, it’s not easy for two proud people who have sworn publicly never to marry to make a reversal.

Beatrice’s line, “I can see a church by daylight,” says a lot about her approach to this relationship, Williamson says.

It means that her eyes are open, that she can see what’s clearly in front of her.

“It’s not blind,” Williamson says. “It’s a proud person saying, ‘OK. There’s not much I can do about it. I love you and we’re going to be together and that’s who I am and you are who you are.’”

The battle of wits provides the attraction.

“I think there’s something hot about having minds that can argue like that,” Williamson says.

Williamson, a fixture at Boscobel, took last year off and made a marvelous turn in “Cyrano” with Kevin Kline on Broadway. This summer, she returns for an 11th season to the tent overlooking the Hudson Highlands, and to Beatrice, a role she has played three times before.

O’Connell is tackling Benedick for the first time.

“I’ll be gentle,” coos Williamson, laughing.

Williamson’s summers at Boscobel have prepared her for the dramatic shift from a blank rehearsal hall in Chelsea to the wide-open spaces of Garrison.

“When you get (here), you feel your shoulders relax and you sigh and you breathe differently,” she says.

The improvisational nature of the enterprise “makes you vibrate at a higher level because you don’t know what’s going to happen and the audience feels that. And when you’re all outside, you all get wet, you all smell the skunk and when the lights go out, you’re all in the dark.”

“It’s like when you go to see a play and there’s a mistake and the actors kind of break and everybody laughs. Everybody walks out going ‘Wasn’t that great? Wasn’t that fantastic?’ It’s that same feel and I think that’s what people like about Hudson Valley. … We figure out some things in the city, but the tent is where the breath comes into the thing.”

O’Connell, in his sophomore year at the festival, says the setting at Boscobel — a large lawn, a large tree and a spectacular view of the Hudson and West Point — provides a set, despite the lack of flats, doors or many props.

“When you make an entrance from far off, you’ve effectively made the world, everything you can see, the stage.”

Ten years removed from her last turn as Beatrice, Williamson says she comes at the character from a different place this time. For one thing, she and fellow festival regular Kurt Rhoads have been married 25 years.

“When you first get married, there’s hope and reaching and there’s love,” she says. “And after being married 25 years, you’ve gone through all sorts of horrors and ups and downs, so there’s a kind of idea of what marriage is and what life together is that is not like a newlywed’s.

“Katie and Ryan just got married last year and it’s interesting that they’re playing Hero and Claudio,” Williamson says. “I feel a little like the baggage I bring to Beatrice is that love is certainly not smooth sailing and it’s a bit of a rollercoaster, but hold on and it’s totally worth it.”