Before your speech go to different female attendees and give them some little token without the grooms knowledge and some key word that they will come forward to the groom and return to him. Then when you give your speech start talking about what a ladies man the groom was and a lot of his secret loves that have pinned for him and had a secret crush on the groom prior to his marriage now want to confess their love. One by one the women will have a cue where they will come forward to the groom to return the item that represented the secret love or admiration of the groom. Young through Old women should be used. Then relate that these women had contacted you and wanted you to tell the groom that they have now surrendered and understand there is no hope of their love for the groom and that they now know they cannot have a relationship and that it is over. Then for the final person have one of the groomsmen or other male attendees come forward to give the final object back to the groom. The crowd will be in stitches as will the groom as none of the people will have been either a secret admirer or former lover of the groom.
You could do what my son did. He was so overwhelmed with emotion that he cried. Enough said.