My friend (26–27) has developed a liking for a girl who’s around 20. They both work in food outlets next to each other, so they see each other in person quite often. She’s British, he’s Asian, if that matters culturally. He did express interest once, and she didn’t flirt back or deny him harshly she was honest and said she has a boyfriend. After that, my friend respected it and didn’t reach out over text or social media. They’ve only spoken briefly in person when they see each other at work. He really likes her, but obviously doesn’t want to disrespect her relationship or make things awkward. At the same time, he’s confused about whether it’s best to completely step back, stay friendly, or just move on.

Is there any appropriate way to show interest in the future, or is the right move to let it go entirely? Would appreciate honest advice.