As for me, I daily wished more to please him: but to do so, I felt daily more and more that I must disown half of my nature, stifle half my faculties, wrest my tastes from their original bent, force myself to the adoption of pursuits for which I had no natural vocation. He wanted to train me to an elevation I could never reach; it racked me hourly to aspire to the standard he uplifted. The thing was as impossible as to mould my irregular features to his correct and classic pattern, to give to my changeable green eyes the sea-blue tint and solemn lustre of his own.
– Charlotte Bronte
Jane Eyre, Chapter 34. As Jane tries to please St. John, she learns that in order to do so she has to become somebody she is not. Jane has always been her own person, someone of integrity who treasures independence and freedom. The manipulative and controlling St. John continues to force her to change her own nature and adopt pursuits she finds impossible. Using a simile she compares this to trying to mold her irregular face to his correct features, and change her green eyes to the sea blue of his.