When at least one man or woman is seeking or engaged in a marriage to a partner purely for fortune: i.e., the fortune of the partner.
When the fortune comes from elsewhere (e.g., seeker must marry to inherit own family's fortune). This element typically is comedic - particularly when a female gold digger crowd learns about bride bounty, and that leads to a flood de femmes.
When the seeker's schemes are more nefarious than matrimony (e.g., absconding, or supporting a paramour/accomplice).