05-11-2018, 03:37 PM
This Japanese sentence does not make sense as it is.
Adding "私がおどろいたのは:WATASHI GA ODOROITA NOWA;what I was surprised at was", it make sense as "I was surprised at the fact that he believes he could make friends by one week effort".
In this case, "に:NI” corresponds with "at".
Does this help?