Earlier quoted context omitted.
The first sentence states he fell "head over heels" in love with her even though nowhere in the piece does he indicate they ever dated or flirted or so much as kissed. The rest of the first paragraph describe an interaction that sounds to me like she was probably trying to deflect his interest. He goes on to say he persisted with a tenacity he did not know he was capable of. If that doesn't sound borderline stalkeris…
Oh come on. The author never harassed her caused any harm or did anything she refused. He was a suitor and had a crush. Stalker is a word better used more carefully in my opinion, for bad people. Not hopeless romantics perusing hopeless relationships.
Let me reframe that:
If there is no hope she will ever say "yes", he knows that and pursues her anyway, he is a stalker, not a hopeless romantic.