I--主语
am unable to find --谓语
any warrant for the belief that any period has offered men the kind of peace and certainty that the modern age is clamoring for.宾语部分
细分起来:
any warrant --宾语
for the belief --定语,修饰any warrant
that any period has offered men the kind of peace and certainty--同位语从句,补充说明belief
that the modern age is clamoring for--定语从句,修饰peace and certainty