Scenario: It's night, and a man is walking home. He sees ahead there is a woman going in the opposite direction as him. Knowing not to stop or approach her, but his presence makes her nervous. What would help further in this scenario if anything?
Keep your hands in view. Fidget a bit if you want.
If you're walking towards her, take a glance at her from about I'd say 5-10 meters away.
Walk a clear path. Pick a lane so she can pick hers to pass you.
Think of something else for a second. Look at a car, building, cloud.
Hit a street sign. You'll make her laugh, she'll feel 100% safe then.
In all seriousness now that should let her know you don't have any dangerous objects in your hand, she'll know you acknowledged her presence, and she'll see you're not 100% focused on her. That's kinda all a girl needs to not be weirded out.