What does it mean when a girl deletes her messages?

Look at the last few exchanges before the thread disappeared. Was the conversation already fading, with slower replies, shorter answers and fewer questions coming back to you? Or was it going well and then stopped suddenly? A thread that was dying anyway tells you she was probably ready to close it. A thread that was active and then vanished could mean she met someone else, got pulled into something stressful, or simply tidies up her phone after a few days. Also check whether she has done this before with other people, since some people wipe everything routinely. The deletion alone rarely tells you much. What matters is whether the pattern before it looked like interest or like a slow exit.

A good follow-up gives her one low-effort thing to respond to. That usually means a light, specific reference to something you had discussed, or a plan that is easy to say yes or no to, so she can choose to continue without it feeling like a big decision. What it should not do is mention the deletion, ask whether something went wrong, or pile on context about how much you enjoyed talking. Leave out apologies for nothing, and leave out any question that requires a paragraph back. Keep the message short enough that answering it costs her almost nothing. If it is a reply that she can easily ignore without feeling bad about it, you have done the job.

Timing matters more than wording here. Send your message in the middle of the day, not late at night when it reads as needy or like you were sitting there watching the screen. Give it at least a few days before you follow up again, and do not send a second message if the first one gets no reply. If she does respond, match her energy and keep the next message just as light. If there is no answer after one follow-up, stop there. A deleted thread followed by silence is a complete answer, and continuing to message will only make the situation harder to recover from if she ever wants to talk again.