My friend

I think my best friend likes me. She used to make flirtatious jokes, but in the last year, it's stopped being a joke. She's lesbian and I'm bisexual, but I only see her as my best friend. We've been friends for four years and we know everything about each other. She constantly wants to meet up with me, sends romantic videos, gets upset when I'm late in responding to her messages, and wants to do the date things that couples do with me, especially the romantic ones. She's my best friend, and I don't know how I can refuse her. She's going to another country next few months, and she'll definitely ask for my opinion before she leaves.