It's followed near immediately by Mood Whiplash, but Benedick and Beatrice finally admitting they love each other and Benedick's heartfelt "Come! Bid me do anything for thee." That is love.
"I do love nothing in the world so well as you: is not that strange?" Sweetest declaration of love ever.
And Benedick swearing he will challenge Claudio, all because Beatrice asks him to, even though neither of them have any proof that Hero has been falsely accused. Recap: Benedick loves Beatrice so much he is willing to challenge his best friend on nothing more than her say-so, simply because he believes her that much. Catherine Tate and David Tennant in the 2011 production, especially, showed the whole damn world just how that scene is done.
This troper owns a DVD of a Canadian production that really did that scene well too. Towards the end, when Benedick goes to kiss Beatrice's hand before going to challenge Claudio, the actor in this production starts going for the traditional hand kiss (the production was set in the Edwardian era) but changes his mind and kisses her palm very intimately and romantically. Then, as he turns to go, she keeps hold of his hand and they linger for a few seconds as they can't bring themselves to let go of each other. It's incredibly sweet.
Depending on the production, Beatrice's "let him down easy" moment with Don Pedro can be this, as she basically tells him he's too good for her. In Kenneth Brannagh's film version the scene is particularly sweet, coming across as just two old friends mutually deciding they're Better as Friends.
The Whedon version plays it more for laughs, but Pedro is obviously trying to cheer up Beatrice by giving her a target for her wit and a distraction from her turmoil after Benedick took offense at her description of him and refused their usual verbal banter as a result.
Benedick may have cracked a few jokes at Hero's expense at the beginning of the play...but when she's falsely accused at the altar he believes she's innocent and supports her pretty much from the start, when even her own father starts cursing her. When he challenges Claudio to a duel, he's not just doing it for Beatrice's sake but also because he's genuinely outraged at his friend's treatment of Hero.