I need help i think my best friend is pretty but she dont think she is. Wat do i do?

My friend is pretty 2 me. and i not jus sayin that cuz she my friend.my lil sis and my cuzin say that. But she dont think she is. Like wen my cuzin tld me 2 tell her that she is pretty She said "she was talkin abt me, Are u sure?, Thats a 1st" And she dont get attention 4rm boys she neva had a boyfriend. but she is pretty.