I assume that you can do it.
我假定你能做。
I presume you can do it.
我认定你能做。
Even assuming a great willingness on the part of all our friends to help, we must not forget that few of them are properly prepared for it.
尽管我们假设只有部分朋友是情愿,帮忙的,但我们不能忘了他们中的少数是真的准备了的。
Even assuming a great willingness on the part of all our friends to help, few of them are properly prepared for it.
上面两个表达方式都是正确的。