Imho I don't like this kind of MC, he can't even say something when accused of being a stalker. C'mon bro, grow a pair.
Also, she's the typical perfect girl in this kind of romance: she loves MC no matter what, even when the engagement (and the backstory) doesn't make sense, an old lady got help by this guy and in less than a day they already talk about an engagement? How the hell did she find him? Why would you give your daughter to a guy you didn't ever meet? And for the backstory: why would you, IN THE MIDDLE OF YOUR MOTHER FUNERAL, give flowers to a casual girl on a swing?
Love the "antagonist", true chad that hates wimps: "you, with a perfect girl? Be real, otaku." He actually slaps you like life does, making you understand that this kind of love stories don't exist, and probably in a RL-situation he would be the actual BF. Tbh I hope in a justified NTR.