I like him but as a friend only!

“f 19 ,  im bit confused wht to do? My close frnd nd ma brother’s frnd as well,,, loves me alot! Even he proposed me….but i denied. He’s all good. He’s so serious nd in future he wanna marry me… He told me each n every thing bout his family n all dat. But problem is dat, ma parents had commitd me wid my first cozn. He is a good guy. I like him but as a frnd only. I like my dat close frnd but there is no love scene wid me… I never love anyone yet. My thoughts r positive.. So guyz plzz help me.. I dnt know, wht should i do? My dat frnd n my cozn’s hopes r getting high each day..( they dont know each other n dis thing )
frndz plz..?