If you're approached by someone who is gay and expresses romantic or sexual interest in you, and you're straight, it's important to respond with respect and kindness. Here's an example of how you might handle the situation:
"Thank you for your compliment (or interest), but I think it's important for you to know that I'm straight. I hope we can continue to interact respectfully."
Remember, someone expressing interest in you is a form of flattery, even if you don't share their feelings. It's essential to communicate your feelings honestly and respectfully, acknowledging their courage for expressing their feelings, but also being clear about your orientation. Honesty, kindness, and respect are key.