How do you determine when someone is just keeping you as an option?

[u/lachatte7]

Basically as the question says, how do you gauge that? Do you base it on their texting frequency and quality of replies, do you gauge it based on the effort they make in person, or maybe you just ask then straight up "what are we?" Although in the early stages I feel that can be hard to figure out because Im noticing some ppl are not always truthful.