When she says, "Now we have found each other," what is Anne talking about in in Anne Frank: The Diary of a Young Girl?

What she is talking about here is an episode from quite late in the book.  She is talking about a feeling she had while spending time with Peter Wessel.

In this episode (page 218 in one copy of the book, at least), she has been sitting with him on a couch.  They sort of accidentally start to kiss and she is overcome -- they come to be "clasped" and "in a whirl."  So she is having a sort of a young love moment.  She will later realize Peter is not for her, but for now, she feels a strong emotion.  That is what she is talking about when she says they have found each other.