In their book "Compact complex surfaces", W.P. Barth, K. Hulek, C.A.M. Peters and Van De Ven refer to the following theorem:

Let $X$ be a compact complex space and $L$ a holomorphic line bundle on $X$. Then $L$ is ample if and only if the folowing holds: given any irreducible analytic subset $Y$ of strictly positive dimension on $X$, there exist an $n=n(Y)$ such that $L^{\otimes n} |_Y$ has a section which has at least one zero, but does not vanish identically.

They don't give a proof in their book.Instead they refer to Grauert's original paper which was published in Math. Ann. 1962. (I'm sorry I do not know how to type the title of the paper because it is written in German.)

I do not know German. So my question is: Can I find the proof of this theorem somewhere else? Or instead, some comments on the idea of proof will also be very helpful.

Finally, this paper of Grauert is among one of the papers I want to read with greatest enthusiasm. Is there a translation? Or can I find some books or papers which give an explanation of the results of this paper?