Generally speaking, when two fighters go to a pre-match face-off and weigh-in, they are looking to intimidate their opponent. Even if it takes the form of some unusual tactics.
In a pre-match meeting between Ewa Brodnicka and Edith Soledad Mattyhsse for a WBO world title, Brodnicka gets a close face-to-face with Mattyhsse and then gets really close when she plants a kiss right on her lips. Brodnicka pulls back with a smirk on her face but then get slapped right in the face because I'm pretty sure that's sexual assault.
Matthysse was for sure fired up after the incident and undoubtedly used it as fuel for the fight. Unfortunately, she would end up losing the fight the next day.