How to respond to "Let's hang out sometime"?

The same sentence means different things depending on the thread. If you've been trading messages for days, asking real questions and her replies are getting longer, then "let's hang out sometime" is usually sincere, just unscheduled. If the chat has been thin, her replies are one or two words, and this line arrives as a way to close things, treat it as a soft no until she shows otherwise. Look at whether she asked you something back in the last few messages. A person who wants to meet tends to keep the conversation moving toward it, and a person who is wrapping up usually stops asking questions.

Also check the timing. If you've only talked for a day, a vague invite is normal and you should move quickly to something concrete. If it's been two weeks and nobody has suggested a time, the vagueness itself tells you something. Either way the read is only a guide. Respond to the tone you actually see, not to the one you're hoping for.

Good replies here share a shape. They accept the idea, attach one concrete option, and leave room for her to change it. The option should be easy to say yes to: a place you both mentioned, a specific activity tied to something she said, or a short window like an evening later this week. Avoid anything that needs a long commitment on the first try, and avoid making the option sound like a big event.

The tell of a good draft is that it contains a real detail from the conversation and a clear proposal, but it doesn't end with a demand. Leave out apologies, leave out jokes that make her defend herself, and leave out multiple questions in one message. If you find yourself adding "or whenever works" three times, you've weakened the offer. One suggestion with a little flexibility is enough.

After you send the reply, give it a real window before anything else happens. If she responds with a yes or a counter-suggestion, that's your signal and you can lock in the details in one message. If she replies warmly but doesn't commit, you can ask once more, ideally with a different option rather than the same one repeated. If there is no reply after a day or two, a single light follow-up that references the plan is fair. Something that makes it easy to answer with one word.

Stop after that. Two unanswered messages in a row is her answer, whatever the reason. Chasing past that point turns a missed plan into an uncomfortable exchange. The better move is to let the thread go quiet and, if she was interested, she will usually come back with her own idea later.