Part of my mlp nex gen universe.  
Yea, in show Trend was introduced to us like character, who little bit stupid. But no matter what, I like how their two looking together. On this basis i do little headcanon of Trenderhoof personality.  
So, he is a familiar hipster-pony, who was a traveling writer, by nature very gentle and sentimental. He was birth and rise in Manehattan. Trenderhoof was 23 years old when he meet Applejack in Ponyville, in this moment he was a ready to start a family, actually want this well. But his courtship scared AJ away (FAILD)  
Second occasion when he saw her, was Grand Galloping Gala. On this time Trend learned from own mistakes, and everything turned out better than last meeting. Trend is a family pony, and appreciates honesty, this it what he and Applejack in common.  
Welp, this shipping I saw interesting because Applejack and Trenderhoof union are opposite by temper, but common in principle.