It's a bit of a stretch that a girl who is that popular and attractive hasn't been confessed to before, especially considering how everyone around her reacted when they saw her walking down the street.
Then again, it could be that she's known as a powerful adventurer, so everyone is too scared to try, out of fear of if they anger her.
Also, asking for marriage in the first sentence would probably get a strong reaction from anyone, but usually not a good one.