You should know, if you haven't seen this, that it's a love story with an espionage/intelligence background, rather than a suspense movie with romantic elements. Actually the only suspense revolves around whether Bergman & Grant will ever stop bickering and get together permanently. Espionage-wise...the cast and the audience all know from the start that Claude Rains is a neonazi who's up to something, so the only mystery is "specifically what is he up to?" Not that compelling a question. And the intelligence techniques that are used to find out are aimed toward advancing the love story, at the expense of reality--does Bergman really need to marry Rains to find out who goes to his dinner parties? Couldn't the mysterious intelligence agency that recruits her just have posted a guy across the street to take notes? Bergman and Rains are very good, Grant less so (he plays almost a Gene Hackman character), and Hitchcock--with all due respect--has done a lot better.