As a young fashionista, Junko Enoshima is described as simply "not fake", charismatic and eager to try new things. During her first appearances, she comes across slightly air-headed and hot-tempered. In the official artbook, she is described as a person who "drips with dissatisfaction the moment she opens her mouth" and tends to be in trouble with her classmates. She is also mentioned to be a bit too talkative with an overly carefree attitude. However, her real personality, revealed at the conclusion of the Killing School Life, is notably different: very apathetic and easily bored to an unhealthy and abnormal degree. Because of this, her behavior and mannerisms tended to be extremely erratic and unstable by her own autonomous design; keeping up one "appearance" for too long bores her, which causes her to often switch between different personas. However, she is capable of maintaining one persona for extended periods of time when necessary. Junko's "moods" included (but were not limited to) her Monokuma persona, sickening cuteness, severe depression, clinical sophistication, boisterous vulgarity, eerie stoicism, and haughty superiority.

Above all, Junko was deeply obsessed with despair, having found despair to be the most (and possibly the only) enjoyable emotion for her, whether it be inflicting despair unto others, or suffering from despair wholeheartedly. This made her extremely dangerous, as she wished to make the whole world feel absolute despair. However, this also often proved to be her biggest weakness, as she gave her opponents a "fair" chance to defeat her in order to make their despair all the greater if they fail, and happily welcomed her own despair if her plans failed. Junko herself have confirmed that she truly has no reason to do the things she does other than despair itself, which makes her all the more dangerous and unable to be reasoned with. However it is hinted at in the anime that her analytical talent was what caused her to turn to despair, and that Hope's Peak was her first target because they see talent as hope, and use that talent for their own benefit, which drove Junko to take the talent they loved so much and use it for evil, which shows her in a more understandable light. It's also shown that under her amnesiac state, Junko doesn't show a thirst for despair or particularly strong hatred of boredom, implying that her constant case of forgetfulness had spared her from embracing despair again.

Junko was shown to be highly intelligent, cunning, somewhat impulsive, extremely manipulative, and violent and cruel without remorse. She was a highly toxic individual, being both physically and mentally abusive to everyone around her. She manipulated people into falling madly in love with her and used their weaknesses, their despair, against them. Things like hope, peace, and happiness disgusted her, but she sometimes gave hope to others, only to turn it into greater despair later. She often manipulated people into doing bad things instead of directly doing them herself and then had a habit of blaming these manipulated people and claiming it wasn't her fault, as a part of proving her point that despair exists in everyone and that hope will naturally lose to that despair. While she is very skilled, Junko can also lie and cheat to further her own goals, even if it's hypocritical and goes against her beliefs. It should be noted that even though she claims despair is the great unknown, in the end, the road of despair went exactly the way she had planned. Despite that she can be cruel and abusive to some, Junko is actually capable of feeling love to those she's close with.

If you could sound similar to her English VA, Jamie Marchi, that would be great, but it is not required!

I don't have any English VA examples as there is not many I can find on Youtube, so if you could try and match the dub voice, it would be great, but again, it is not necessary.