tell her you have developted feelings for her and tell her the reasons of why you are in love with her or like her, after it if she stays silent dont make her uncomfortable and tell her that if she doesnt know how to answer or doesnt know how to react she could answer some other time and plan another day to go out and when she is ready she will tell you how you feel, dont be scared to be rejected, and try to confess on a park or at any place you could be alone and safe, good luck <3