he believes that this very difficulty may have ha

he believes that this very difficulty may have ha

of 后的宾语 forcing him to think long 是动名词短语，整体作 advantage 的后置定语，意思是 “迫使他长时间考虑的 (有利条件)”，并非是你认为的 advantage of forcing 或者 forcing advantage 这种简单修饰关系。
〔参考译文〕 他相信就是这种困难或许会具有迫使他长时间思考的补偿性的有利条件。