꽃보다 남자 = Boys over flowers or flower boys :) ;P

"학교 = school

that's all.. I don't understand the rest of the sentence.. :)))

밖에서는 = aside from/ only..... I'm not really sure but I've heard this many times in kdramas :)

특별히 아는 척 = ?? :(

해줄게 = will do

I'm going to pretend as i know you just outside of the school

Speaker is a rich guy and listener is ordinary girl. He likes her but he is culmsy to open his heart

I don't understand the English sentence or the Korean sentence. What would be the purpose for pretending? Pretend what?