Ms Begum is challenging a Government decision to remove her citizenship.
She fled her east London home as a 15-year-old schoolgirl to join ISIS more than seven years ago.
It has been alleged that she was smuggled into Syria by a Canadian intelligence agent.
And a watchdog has warned that terror suspects like Ms Begum could be treated like victims if they exploit slavery laws.
But journalist and filmmaker Andrew Drury has cast a damning light on her character.
Shamima Begum fled to Syria as a 15-year-old
PA
Shamima Begum in Syria
GB News
Mr Drury claims Ms Begum, now 23, "thought she could manipulate" him into thinking she is a victim of trafficking.
But he said a "slew of bizarre texts" convinced him "she is a bitter, twisted character with deep psychological problems".
The journalist adds that Ms Begum told him the death of her three children "doesn't make her feel sad anymore".
And, he writes in The Sun, she blamed Vladimir Putin's invasion of Ukraine for turning the spotlight away from her.
Mr Drury says he first met the ISIS bride in June 2021 as he visited Syria to film a documentary, called Danger Zone.
He says he initially "felt sorry for her" and "genuinely thought she was a victim" but changed his mind after getting to know her.
Ms Begum was nine months pregnant, in a Syrian refugee camp when she was found in 2019.
Her British citizenship was revoked on national security grounds shortly afterwards.
She decided to challenge the Home Office’s decision to remove her British citizenship and wanted to be allowed to return to the UK to pursue her appeal.
In July 2020, the Court of Appeal ruled that “the only way in which she can have a fair and effective appeal is to be permitted to come into the United Kingdom to pursue her appeal”.
The Home Office challenged the decision at the Supreme Court four months later.
The Supreme Court ruled in February 2021 that Ms Begum should not be granted leave to enter the UK to pursue her appeal.