assure 与ensure 在用法和意思上有什么意思?

assure
KK:[]
DJ:[]
vt.
1.向...保证,担保[(+of)][O5]
I can assure you of the reliability of the information.
我向你保证这消息可靠.
ensure
KK:[]
DJ:[]
vt.
1.保证;担保[O9][+that][+v-ing]
I can't ensure his being on time.
我不能保证他的准时.
用法差不多