Plain and Pragmatic
Chambers's writing style—or should we say Geertrui's, at least half of the time—is plain and pragmatic, almost journalistic. When describing the events of WWII, or the present day, what happens to Jacob or Geertrui and how they feel about it is presented pretty directly.
So even though we're not living in the 1940s, we still get what's happening between the young couple, in addition to what Geertrui thinks about it fifty years later. In fact, whether describing the past or present (or even future for Geertrui sometimes), Chambers is committed to involving readers in his text, almost like he's talking directly to us. For example, check out what Geertrui writes when considering death:
It is when success seems to be almost in your grasp that you become aware of how fragile is human existence, and of the unending possibility, almost the inevitability, of failure. And this makes you hesitate. (2.42)
Although Geertrui's supposedly addressing Jacob here, when she says "you," it's hard not to feel implicated. Geertrui's clear and realistic here, she explains exactly what it feels like to be in a war and be confronted with death. It could be really challenging for someone to share such deep, dark thoughts with us, but not for Geertrui—she calls it like she sees it.
She also tells us why she's got time to do this writing and what the purpose is. After all, she wants Jacob to learn the full story, not the short version—she's on her deathbed, and she wants to be able to express herself in English properly to get the whole story out. This also tells us something about Geertrui's character: even in her last moments before death, when she'd be totally justified in getting a tan and drinking mai tais, she doesn't rest on her laurels—instead, she describes them.