Sometimes interest, sometimes "why is this dude staring", sometimes judging,... so it depends on the type of look she's giving him

This is interest, no doubts. But women are more complex than us. They can supress their animalism, biological search for met.... There selection of mate is complex..... They don't even know what they want and "No" mean may not be no..... Usually they are checking how committed you are. Ask again with confidence when the situation allows, they are paranoid so make sure it is a safe environment for her to express her self, Meaning no one around to judge, where she feels safe balabla.....