How to respond when she says that sounds fun but I'm not free

When she says the idea sounds fun, she is telling you two things at once. The first is that she liked the suggestion. The second is that the timing or the logistics are wrong. People say "I'm swamped" when they really are swamped, and they say it when they are not sure how interested they are yet. You often cannot tell which from one message.

Read the reason she gave. A specific reason, like a deadline or a trip, usually means the no is real and the interest may be too. A vague reason, or one that comes with no alternative and no question back to you, can mean she is keeping things light. Look at what she did with the message around the no. Did she ask a question, mention what she is doing instead, or say something about you? Those are signs she wants the conversation to keep going.

A good reply does three jobs. It accepts the no without argument, so she does not have to defend it. It keeps the conversation moving on something other than the plan, so the exchange does not end on a logistics note. And it leaves one small door open, framed as an option rather than a new ask.

The door works best when it is specific and cheap to walk through. Pointing to something you both mentioned earlier, or a neutral comment about her week, gives her an easy reply that does not need a calendar. If she engages with that, you have your evidence of interest. If she only answers the surface of it, you have learned the plan was the only thing on the table.

Give the conversation a natural gap of a day or two before you check back in, and only if she has not already picked the thread up. A message late at night or first thing in the morning tends to feel more pressing than a midday text, so pick a normal hour. Your follow-up should be lighter than your first message, not heavier.

If she replies warmly, you can make a concrete suggestion for a new time. If she replies with a short, flat answer or nothing, let it go. One gentle follow-up is reasonable. A second push after a weak response tells her the no did not count. Stop there and let the conversation go quiet, which is also a fair outcome.