In this clip, Natasha Romanoff has the task of persuading Bruce Banner to join the Avengers. She uses several persuasive techniques including innuendo ("I'll persuade you"), and extreme consequences ("We're facing a potential global catastrophe"). Her initial tactic, however, is that of "Jigsawing." That is to say, landscaping the situation to promote intergroup harmony and positive social relations. It is used here as, before asking for Banner's help, Natasha lets him know that they've been keeping people away from him to help him out .
This technique is detailed in Aronson, Blaney, Stephan, Sikes, and Snapp's (1978) experiment. Participants were students in whose class Aronson and colleagues implemented a technique which allowed students to work with other students from different backgrounds. These intergroup relations improved academic performance and minimised prejudice. In the example above, Natasha hopes that by making Banner think they have a friendly relationship he will agree to do as she asks.
Aronson, E., Blaney, N., Stephan, C., Sikes, J., & Snapp, M. (1978). The jigsaw classroom. Beverly Hills, CA: Sage.