Surprised you with it, not quite forced it on you, but almost - though the assumption would be that of course she could have said no. To spring, in this usage, is start something without discussing it first. Often, people use the phrase "to spring a surprise". https://www.oxfordlearnersdictionaries.com/definition/american_english/spring_2

When "you are sprung on someone" you are so in love and infatuated with them that you're almost obsessed and want them so badly that in a way it physically hurts, so the man in the movie intended that he want to literally have sex with her because he's extremely attracted by her