How to reply on Hinge when she says she wants to keep chatting but is tired tonight

When she says she's fading but wants to keep talking, the sentence is doing two things. The first half tells you she likes the conversation enough to not want it to stop. The second half tells you she has run out of room for it tonight. Those don't conflict. She's asking you to meet her where she is, which is at the end of a long day with a phone in her hand.

So read the message as an invitation to keep things easy. She hasn't said the chat was boring, and she hasn't said she's losing interest. If her earlier messages were warm and she asked you questions back, the tiredness is almost certainly just fatigue. Check the rest of the thread before you decide what the tiredness means.

The reply should be short enough that she can read it on the way to sleep and not have to answer anything. A line that agrees she's tired and says you're glad you talked is usually enough. If you want to name something you enjoyed in the conversation, pick one small thing, not a list of compliments that asks her to respond to each one.

Avoid putting a question at the end unless it's a very easy one with no real thought needed. A question at 11pm turns the reply into homework. The goal is that she feels relieved and a little warm, not that she feels she owes you a follow-up.

After you've sent the reply, the most useful thing you can do is nothing for a while. If she wants to pick it up tomorrow, she will, and she'll probably open with something she thought of while you weren't talking. That tells you more about her interest than anything you could write tonight.

If she doesn't reply the next day, one short message is fine, something that refers back to what you talked about. If that gets nothing either, stop there. Two unanswered messages after a night where she said she was tired is enough for most people to read as a fade, and sending a third only makes the exchange feel heavier than it was.