The question “How to propose a girl who doesn’t talk much to boys” sounds like it was either posed by an Indian person who doesn’t speak English all that well, or a bot.
Bots nowadays are rather good at generating grammatically sound sentences. The issue is usually not conveying meaning, but that doesn’t happen with OP.
If the issue is the lack of “to” after “propose”, keep in mind that verb regency can vary even among native speakers of a language. So while “propose a girl” might look incorrect for a Canadian or American, well, it’s on the same level as a Brit complaining because you forgot the U in “colour”.
The question “How to propose a girl who doesn’t talk much to boys” sounds like it was either posed by an Indian person who doesn’t speak English all that well, or a bot.