The role of the black widow in "The Avengers" can be described as a kind of love, showing mercy everywhere, being interested in almost every man, and being ambiguous, but I think the black widow likes the Hulk, which can be proved by the following points.
1. In Avengers 4, the Hulk doesn't want to show his powerful appearance for various reasons. It is the black widow who has been with him and untied his heart. Moreover, the black widow is really kind to the Hulk, and it can be seen from her eyes that she loves someone. I can see that the black widow is full of love for the Hulk. Although she is very enthusiastic about every man, she feels very different about the Hulk.
Second, the black widow shed tears for the Hulk. Although it is easy to shed tears, it is obviously different to shed tears for one's beloved. It can be seen from all kinds of behaviors of the black widow towards the Hulk that her love for him and a person can't be hidden. The good of the black widow Hulk is sincere, and it is a kind of unrequited love.
Third, the black widow is particularly patient in transforming the Hulk. Because at the risk of being killed by the powerful Hulk, almost no one is willing to control the Hulk's emotions, only the black widow, only she is willing to use herself to warm the Hulk, so that he can have reason and restore his original body at an appropriate time.
Apart from other things, I like the role of the black widow very much. I want to say that she died too hastily in the end. I always thought that she would come back to life. Who knows that she lost her life just for that spar? I like her courage and dare to love and hate. She is a very good heroine. I think the black widow still loves the Hulk.