Try using this:
My dearest Sarah,
As I write this, the mud squelches beneath my boots and the ever-present boom of artillery echoes in my ears. The air is thick with the smell of cordite and the acrid stench of death. This is not the world we knew, Sarah. It is a world where men are reduced to shadows, faces etched with fear and fatigue.
We huddle together in the trenches, sharing stories and memories to keep the darkness at bay. The camaraderie is strong, Sarah, forged in the fires of shared hardship. We look after each other, brothers in arms bound by a desperate hope for survival.
But fear gnaws at us all. The constant threat of attack, the sight of fallen comrades, the knowledge that home may never be reached – these burdens weigh heavily on our hearts. Sometimes, Sarah, the world seems to shrink to the muddy confines of this trench, and the future stretches before us as bleak and desolate as the landscape around us.