She has quite an unusual name. She explains that it's a combination of the first letters of the following Pokémon: Teddiursa "Te" (Japanese: ヒメグマ Himeguma "ヒ" "Hi"), Mareep "ma" (Japanese: メリープ Merriep "メ" "me"), and Cubone "cu" (Japanese: カラカラ Karakara "カ" "ka").

Temacu is one of the few girls to fall in love with Brock. While she was running to catch her Nidorina she nearly tripped and fell into a fountain. But Brock caught her in time before she fell. Since that moment she "knew" that she had to marry Brock and even started to picture what their wedding would be like. Instead of Brock being overjoyed by this, he acted confused and unsure.

However, this feeling for Brock didn't last long. Team Rocket attacked her father's laboratory and thought they had captured a Pokémon; instead, they actually caught Temacu. As she tried to get out of the balloon she nearly fell again but this time James was there to catch her. This caused her to now fall in love with James and now she wanted to marry him. Feeling that they could get their hands on the Pokémon at the lab, Jessie and Meowth forced him to play along, even if it meant marrying her. James was not at all comfortable with this idea.

Team Rocket then change outfits and Temacu made up a story that James had saved her from the "terrorists" when she introduced him to her father.

Once Brock found out that Temacu had now fallen for James, he was crushed, since by this point he was starting to fall for Temacu. Soon, Misty pulls off Jessie's disguise and Team Rocket makes a run for it. When they were trying to escape, She ordered her Poliwhirl to attack James with Water Gun. Temacu, worried for James' safety, jumped in front of the Water Gun attack and then fainted.

Later on, her father explained that she recently saw her cousin get married and that's why she was so obsessed with getting married herself. Soon Temacu came to and, yet again, fell in love with someone else. This time it was her doctor, who returned her feelings.

[credit to bulbapedia]