Nora wasn't a trusting person. she never liked trust exercises, or telling people her secrets- even as a schoolgirl she never spoke of crushes. talking for hours without giving any important information about herself was her talent.
Sam made Nora comfortable; never pushing her to answer questions about herself, or pressuring her into things she wasn't ready for relationship wise- so she trusted him.
Sam wasn't as faithful as Nora assumed.
Up goes the first brick.
