The motive could be related to a family feud. Maybe the saleswoman is related to someone the kidnapper has a problem with. It could also be that the kidnapper is trying to use the saleswoman as a bargaining chip in some other situation. For instance, if the kidnapper is involved in illegal activities and wants to use the kidnapped saleswoman to negotiate with the authorities to avoid prosecution. There is also a chance that the kidnapper is simply acting out of desperation, thinking that by kidnapping the saleswoman, she can solve her own problems, whatever they may be.
One possible motive could be jealousy. Maybe the kidnapper woman is jealous of the saleswoman's success or the attention she gets from customers. Another motive might be related to a personal grudge. For example, the saleswoman might have unknowingly offended the kidnapper in the past. It could also be a case of misinformation. Perhaps the kidnapper has been wrongly informed that the saleswoman has something she wants, like a valuable item or some important information.
One possible motive could be financial gain. Maybe she thinks the saleswoman has access to money or valuable items at her workplace. For example, if the saleswoman works in a high - end jewelry store, the kidnapper might hope to get hold of some precious jewels through her.
If there are any objects around, she could use them as weapons to defend herself and escape. Like if there's a heavy object like a vase, she could hit the kidnapper (not too hard to cause serious harm but enough to daze her) and then run away. Also, if she has a phone or can get to one, she could call for help secretly.
Perhaps Fleur is being controlled or influenced by a dark force. In the Harry Potter universe, there are many dark magic entities that could manipulate someone into kidnapping Harry. It could be that she is under the Imperius Curse or some other form of mind control. Another reason could be that she has some sort of personal vendetta against Harry or those close to him, and kidnapping him is her way of getting revenge. She might think that Harry has wronged her in some way, whether it's real or just in her deluded perception.
Maybe she's trying to protect Naruto from something she knows about but others don't. She might think that by kidnapping him, she can keep him safe from an imminent threat that the village or his friends are unaware of.
Well, in this kind of fanfiction, Doc Oc could kidnap Spiderman to force him to reveal his identity. Doc Oc might think that knowing who Spiderman really is would give him an upper hand in their ongoing battles. It could also be that Doc Oc wants to study Spiderman's powers. He's a scientist after all, and Spiderman's abilities are quite unique. He might believe that by kidnapping and examining Spiderman, he can find a way to replicate or counter those powers.
She might be a huge fan of the writer and think that by kidnapping him, she can force him to create a novel just for her. Maybe she has some very specific ideas in her head that she wants to see in a novel and believes this is the only way to get it.
It could be that Naruto has lost his sanity temporarily. The stress of being a hero, the constant battles, and the losses he has endured might have taken a toll on his mental state. In this state of instability, he may see Sakura as a symbol of something he wants to preserve or protect, but his way of doing so is through kidnapping. Or there could be a new villain in the story who has the ability to make Naruto act out of character, and this villain's plan involves Naruto kidnapping Sakura.
Well, it could be out of jealousy. Maybe Dean feels like he's losing Ginny to someone else and in a moment of madness, decides to kidnap her. But this is all just speculation within the wild world of fanfiction.
It could also be for power. Perhaps Stiles has some knowledge or ability that Theo wants to use for his own gain. In the show, Stiles was quite smart and resourceful, so Theo might kidnap him to get access to that intelligence or those skills. In some fanfictions, Theo might be trying to use Stiles as a bargaining chip to get something from the other characters like Scott or Derek.
One possible motive could be revenge. Maybe Sam Gh did something to Manny Ruiz in the past that made Manny want to get back at him.