“难于理解的人”可以翻译为 "a difficult person to understand" 或 "someone who is hard to understand"。
这两种表达都清晰地传达了“这个人难以被理解”的含义，具体使用可根据语境和表达习惯选择。例如：
He's a difficult person to understand; his thoughts are always so abstract.（他是个难于理解的人，他的想法总是很抽象。）
She's someone who is hard to understand, with her complex emotions and unpredictable behavior.（她是个难于理解的人，情绪复杂，行为难以预测。）