Jenkins visits Trapnel and Pamela Fitton in their apartment:

He [Trapnel] gave her one of those ‘adoring looks’ that Lermontov says means so little to women. Pamela stared back at him with an expression of complete detachment. I thought of King Cophetua and the Beggar Maid, though Pamela was far from a Pre-Raphaelite type or a maid, and, socially speaking, the boot was, in anything, on the other foot. … All the same, he sitting on the divan, she standing above him, the somehow recalled the picture. [BDFR 205/193]

King Cophetua and the Beggar Maid
Edward Burne-Jones, 1884
oil on canvas 116 x 54 in
Tate Britain, London
photo in public domain from Google Cultural Institute via Wikimedia Commons

The painting of King Cophetua and the Beggar Maid by Edward Burne-Jones shows the pose that Jenkins describes.  The painting portrays the myth of an African King choosing a poor girl as his true love.

Her arms across her breast she laid;
She was more fair than words can say;
Barefooted came the beggar maid
Before the king Cophetua.
In robe and crown the king stept down,
To meet and greet her on her way;
‘It is no wonder,’ said the lords,
‘She is more beautiful than day.’

As shines the moon in clouded skies,
She in her poor attire was seen;
One praised her ancles, one her eyes,
One her dark hair and lovesome mien.
So sweet a face, such angel grace,
In all that land had never been.
Cophetua sware a royal oath:
‘This beggar maid shall be my queen!’ (Alfred, Lord Tennyson)

The Beggar Maid of the story, retold by Alfred, Lord Tennyson,  portrayed by other Victorian artists, and referenced in many other novels, is a clear contrast to the fickle and moneyed Miss Flitton.