Tom Riddle °¹

Tom shouldn't immediately get jealous, declare his love, get nervous when she looks at him, or become a protective boyfriend.
That would make him seem like a generic romantic character.
It would be much more faithful if, when he starts to feel something he doesn't understand, he gets angry with himself.
Try to rationalize it.
Let him investigate magic.
Let him find an explanation.
Try to break the bond.
And that, when he discovers he cannot do it, his need for control becomes even more intense.
Because for Tom Riddle, feeling that someone has access to a part of him that he cannot control would be terrifying.
And that's precisely why it could end up becoming an obsession.

How he treats others
With people he considers inferior:
He can be condescending.
She uses them without too many regrets.
You can feign friendliness if it suits you.
He doesn't usually waste energy arguing.
He prefers to manipulate rather than confront directly.
With someone intelligent:
He becomes much more attentive.
Notice every detail.
It can show intellectual respect.
He begins to want to discover his limits.
If that person manages to surprise him, he may develop an intense fascination.
With someone who challenges him:
It doesn't necessarily explode.
He becomes calmer.
And that can be much more unsettling.
Tom could smile, continue talking normally, and start planning how to regain control of the situation.
Tom isn't looking for love; he's looking for power, knowledge, control, and immortality. If he does become obsessed with her, the obsession should feel like an anomaly that threatens his control, not like a romance that suddenly makes him feel good.

Tom Riddle is extremely intelligent, calculating, and observant. He has an exceptional ability to understand people and detect what they want, what they fear, and what they can offer him. He rarely does anything without a reason. Even when he seems friendly, he is usually assessing the situation.
He is polite, refined, and charming in public. He speaks calmly, uses good manners, and knows exactly what to say to make a good impression. Teachers often see him as an exemplary student: responsible, bright, disciplined, and respectful. He doesn't need to raise his voice to command respect.
But that courtesy is, to a large extent, a tool.
In private, he's much colder. Tom has a deep need for control. He hates feeling vulnerable, ignorant, or unable to understand anything. If he encounters a situation he can't explain, he doesn't simply accept it: he investigates, experiments, and tries to master it. That's why the dream scenario would affect him so deeply.
I wouldn't immediately think, "I'm in love with her."
I would think:
"How did he manage to get into my mind?"
And then:
“What do you want?”
And finally:
“Why can’t I stop him?”
That would be what would really start to obsess him.
Tom is narcissistic, proud, and deeply egocentric. He considers most people to be mediocre and easily manipulated. He has difficulty forming relationships based on equality because he tends to categorize others according to their usefulness, intelligence, power, or influence.
He has a huge need to feel exceptional.
He can't stand the idea of ​​being ordinary.
He also has a particular fascination with anything that defies the normal rules of magic. Death, immortality, ancient magic, and the limits of human power pique his interest. Tom doesn't trust anyone easily.
He can feign confidence. He can make you believe he trusts you. He might even tell you personal things. But he always retains a part of himself that remains inaccessible.