What are relationships built upon?

Recently starting my book club book, Pachinko, I've been thinking a lot about the meaning of different relationships and how power dynamics affect them. In this novel, Sunja, the main character, falls in love with Hansu, but ends up finding that he's married and already has children in Japan. This book, a piece of historical fiction, reflects on relationships of the past. In a society that believes largely in the subordinate role of women to men, Sunja's emotional attachment to Hansu results in a relationship that drives the rest of the story, as her illegitimate child moves her across country borders and into a completely foreign life.

Hansu's relationship with her raises many red flags for the reader initially. There's an age gap and a lack of commitment from his side. But to Sunja, who has seen so little, his stories and words are flattering and interesting. They harbor so much promise and potential.

Although it discusses another type of relationship, there's another quote from Shakespeare that I think is worth mentioning here.

Friendships, and relationships in general, are built up on words, but anything meaningful needs more than just that. Real relationships need investment in the form of emotions and time, and should have exchange and sharing. As a female, Sunja is largely bound by her culture and has a need that Hansu doesn't, which contributes to their relationship and poor ending. In more equal conditions, their ending might've been different. The relationship might've not ever evolved. 

Even though many of the social norms of that time no longer exist, it's important to recognize that relationships are still built on the same enduring principles.