I think the word you probably want is advances, but I guess overture could technically work.
I don't see how you could have no idea how things like this could happen, maybe it is because you are female, there are certain things in life you don't have to deal with as much.
Now there is no justification for a homicide like this, don't get me twisted, its fucked up and monstrous, but if this event really is about rejection, well that explains it all right there, nothing to wonder about.
Being rejected can hurt really bad. All of us have to deal with rejection in life, but in most cultures it is generally the man who has to put himself out there and make the first move, or he will likely be alone forever. As a girl you may not have to deal with this as much, because you probably get propositioned by people so much you feel harassed, but you have plenty of options that actually come to you and seek you out, there is no risk for you, nothing is on the line, you can so no an ignore the guy to his eternal loneliness like its nothing.
Most regular men don't have that luxury. We have to pursue mates and put ourselves out there and take risks and it actually does hurt to then be rejected after you have worked up the courage to make an advance on somebody...especially that look of disgust a girl can give you or look like you are a joke, like why would you think you are good enough to talk to me? like you're stupid or pathetic... it is something that can be difficult to deal with, and I can totally understand why some asshole chads out there who care more about themselves than anybody else can go psycho and murder a girl who rejects and/or betrays him. Men are human too, and can react in all kinds of fucked up ways to pain, as can women.
Women kill for the same kind of bullshit as men, I can assure you, we are all equal. Women can usually find men to kill for them pretty easily too, so lots of times killer women don't even have to get their hands dirty a lot of the time.
Ok Incel