Give a stream of consciousness and then the final answer. There's many a slip' twixt the cup and the lip is a very old proverb, similar in meaning to "do n't count your chickens before they hatch". It implies that even when a good outcome or conclusion seems certain, things can still go wrong.

Answer this question: there is many a slip between the cup and the lip meaning in english?
The important part for answering this question is: It implies that even when a good outcome or conclusion seems certain, things can still go wrong.
So, the final answer is even when a good outcome or conclusion seems certain , things can still go wrong.