While on a quest with Gray and Lucy, Juvia would find herself with them confronted by a Mage with illusion magic. Before they could do anything, the Mage would use his illusion magic to trap them in illusions

Gray was caught in an illusion believing he was surrounded by fire. Lucy was trapped in an illusion where she was surrounded by spiders. Meanwhile with Juvia…

Juvia: Ha! Juvia will not fall for any illusions. Not when Gray… Gray… GRAY-SAMA!!! her eyes turned into literal hearts as she was surrounded by a bunch of Grays in their underwear

Juvia: So many Gray-Samas… Juvia… Juvia's in paradise!!! She squeals in excitement