I just got the idea that an "analysis" or "useful notes" page on both this trope and Stalker Without a Crush could be interesting.
The Other Wiki already has plenty of information on it, including a common classification of different types of stalkers and their motives.
Of those, the "intimacy seeker" and the "incompetent suitor" fit this trope, while the others are mostly Stalkers Without a Crush. There also appears to be a sliding scale between these two.
"Intimacy seekers" have a delusional or near-delusional belief that their victim is the "right match" for them, and misinterpret anything the victim does as a sign of affection towards them. Shrinking Violet versions may be a relatively harmless nuisance, but their attempts to "force their victim into happiness" (or what they think the victim secretly wants) can also become dangerous, especially when they are completely wrong. Rape and other forms of abuse may ensue, as well as violence towards the victim's spouse (if one exists) and anyone who might be a rival. See also Obliviously Evil, Well-Intentioned Extremist, Yandere.
"Incompetent suitors" are basically Dogged Nice Guys/Girls with No Social Skills, who approach their love interest in socially inappropriate ways because they don't know better. Their interest has an obsessive quality, causing them to continue making advances even when they have evidence that their love is unrequited. Typically they are very socially naive, and their advances can sometimes be very childish or silly in nature. Although typically not malevolent, they tend to become obnoxious Trolls in the victim's eyes, and will not understand (or don't want to understand) attempts at rejecting them gently. However, once they get told to "fuck off" with enough Brutal Honesty, they usually suffer a Break The Cutie moment, which can lead to serious consequences like Driven To Suicide or even Woobie, Destroyer of Worlds. See also Innocently Insensitive, Jerkass Woobie, Loners Are Freaks.
In Real Life, many Stalkers With a Crush tend to fall on a spectrum between these two types. Often, but not always, they have mental illnesses or developmental disorders, with "Intimacy Seekers" more often having delusional disorders including erotomania, but also schizophrenia or schizotypal personality disorder, and "incompetent suitors" more often having neurodevelopmental disorders like autism or intellectual disability.
Lastly, there is also a sliding scale between Stalkers With and Without a Crush. There is another type named "Rejected stalker", who has usually had a crush on his/her victim - and also a more-or-less functioning relationship - in the past, but right now their motivation is more seeking revenge for a perceived injustice. Some "rejected stalkers" are former "incompetent suitors" who got rejected the hard way, or "intimacy seekers" who have come to the conclusion that their love interest doesn't want to be made "happy" by them. Others come from a long-successful relationship that has ultimately failed, or they have successlessly tried to "possess" their partner like a pet. Or they may feel love and the need to retaliate at the same time, as can easily happen when you have Borderline Personality disorder (though that isn't required).
Then there are also sadistic stalkers who derive sexual pleasure from repeatedly harassing their victims. Whether this counts as a "Crush" or not is probably YMMV-ish.
The (already mentioned) aspect of gender Double Standards is also interesting. Also notable is that the stalker isn't always the obvious perpetrator: Some rejected stalkers are more broken cuties who have been rejected by a love interest who turned out to be a complete Jerkass. (Although those aren't clear-cut examples of this trope, but either Stalkers Without a Crush, or somewhere in between both.)