This happened to me recently when I offered a third date, and here is what I did:
1) 15 minutes after getting a "maybe", knowing that maybe = no, I withdrew the offer for the date and (in just a few words) called her on her BS.
2) She sent a really long reply but I just made a joke of it. Never drag out arguments, you only make multiple copies of the problem. Know that unusually long replies are often the sign the relationship is over, it's her spinning her wheels, when the Coyote has gone over the cliff but hasn't fallen yet. Possible dump echo. Also a potential sign of high interest though.
3) Knowing I had to head out of town soon, I made an appearance at her work (she is a barmaid), and I was looking my best. We came face to face for a moment, and it was powerful, but then I vanished. I hadn't seen her in 2 weeks and didn't want a month to elapse, knowing that feelings start to fade after 3 weeks.
4) A week later I sent her a photo of her from our second date and told her she was so beautiful I was speechless.
5) She thanked me (I wanted to walk away on a good note).
6) I got 5 other phone numbers, including one of her barmaid friends, who I actually made out with.
7) I then went NC (I was truly speechless). I actually started relocating out of the state within just days, by coincidence. When you drive 1000 miles away from Oneitis, you feel their spell lift like a rain cloud. I knew if she didn't reply by the time I returned to get my stuff in 2 weeks it was over, and I was willing to allow that to happen. Never pursue women with low interest. I must admit, I felt heartache.
8) Note that she didn't know what to expect at this point. My previous 4 texts went from offering for a date, to retracting the offer, to joking, to flattering her. Now I had truly vanished.
9) Eight days later she wrote, sending me sexy pictures of herself. I replied 2 days later, sending her photos of where I was (a much more exciting place). She told me she could tell I was 1000 miles away somehow. She felt my absence. I told her I'd be back in town this week and set up a date for this Friday.
I understood there was a good chance she'd simply let me walk away, and I was willing to.
Know that when two people are together, there will (hopefully) be lots of good things but there will also be a few bad things. Over time, people tend to forget the bad things and remember only the good things. This is why absence makes the heart grow fonder. This is why we must "give her the gift of missing us" (Louis/Copeland) occasionally. Let the myriad little problems fade from her mind.