What is colonialism? Why does Beneatha think Asagai will try to "cure" it in Africa? Consult an encyclopaedia, your history book, or the Internet for help.

In context, a Raisin in the Sun speaks directly to the colonialism in Africa, the British presence that took control of the country, occupying it and exploiting its resources for financial gain. Beneatha believes Asagai will try to "cure" because of the following words:

I will go home and much of what I will have to say will seem strange to the people of my village. But I will teach and work and things will happen, slowly and swiftly. At times it will seem that nothing changes at all … and then again the sudden dramatic events which make history leap into the future. And then quiet again. Retrogression even. Guns, murder, revolution. And I even
will have moments when I wonder if the quiet was not better than all that death and hatred. But I will look about my village at the illiteracy and disease and ignorance and I will not wonder long. And perhaps … perhaps I will be a great man … I mean perhaps I will hold on to the substance of truth and find my way always with the right course … and perhaps for it Iwill be butchered in my bed.
some night by the servants of empire …