Benedick is almost a match for Beatrice as a memorable Shakespearean character. His apparent misogyny and unwillingness to make a commitment to a woman are almost stereotypes early in the play. His use of language, especially in his "merry war" with Beatrice, prevents him from being the clichéd male who refuses to commit to a relationship.
Benedick has probably had a lot of experience with women, only one of whom was Beatrice. He vehemently declares his intent to remain a bachelor and disparages Claudio for wanting to marry Hero, "Leonato's short daughter." He restates his disdain of love and marriage in a monologue alone on stage — even more likely to express his true feelings than his teasing comments to a companion he will lose through marriage. Throughout the early scenes, his exchanges with Beatrice create a feeling that he "doth protest too much" — that is, he really harbors at least affection for Beatrice.
It takes the "noting" scene near the arbor, arranged by Don Pedro, for Benedick to admit he may indeed be able to love Beatrice since she loves him so much. His subsequent meetings with Beatrice and with his friends show a marked change in his attitudes and demeanor from the early scenes. He recognizes that he may be opening himself up for ridicule at his reversal of his well-known attitudes, but he sees his opening up as a part of maturing. His support for Beatrice after the denunciation, including his confrontation with Claudio, demonstrates not only his commitment to Beatrice, but also the value he places on justice even at the risk of loyalty. He becomes single-minded about marrying Beatrice, probably speaking to Leonato about her immediately after the confrontation with Claudio and again just before the wedding. His new behavior finally culminates in his public proposal to her, risking not only her refusal and contempt, but also the ridicule of the assembled company.
Has Benedick changed during the week of the play? Most certainly, both in his public and his private attitudes. That a dyed-in-the-wool bachelor is transformed into an eager bridegroom is extraordinary, yet Shakespeare makes it believable, with a little help from Benedick's friends.