I like you.
The word she uses, 好き, can be translated most directly as "like," despite it also being used in a romantic context. I, for one, would normally translate only 大好き as "love," but that's mostly personal preference. The more you know: the in-progress verb, 愛してる, or "I love [you]" is relatively dramatic, and actually not used often even by married couples actually in love.