Boys/guys with lifelong best friends who have little sisters, have you ever fallen for their little sister? Or do you consider her your sister too?

So I’m a fan not of romance novels but romance in the novels that I read. The whole “brothers best friend” trope got me wondering if there are some guys who really do fall in love with their best friends sister or if that’s something that doesn’t happen?

Boys/guys with lifelong best friends who have little sisters, have you ever fallen for their little sister? Or do you consider her your sister too?
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