If the sentence is true, then it is a lie as it says. But if it is a lie, it cannot be true. A lie cannot also be a truth. So the sentence being true makes it a lie.
ɪ f WORD_BOUNDARY ð ə WORD_BOUNDARY s ɛ n t ə n s WORD_BOUNDARY ɪ z WORD_BOUNDARY t ɹ uː WORD_BOUNDARY ð ɛ n WORD_BOUNDARY ɪ t WORD_BOUNDARY ɪ z WORD_BOUNDARY ʌ WORD_BOUNDARY l aɪ WORD_BOUNDARY æ z WORD_BOUNDARY ɪ t WORD_BOUNDARY s ɛ z WORD_BOUNDARY b ʌ t WORD_BOUNDARY ɪ f WORD_BOUNDARY ɪ t WORD_BOUNDARY ɪ z WORD_BOUNDARY ʌ WORD_BOUNDARY l aɪ WORD_BOUNDARY ɪ t WORD_BOUNDARY k æ n ɑ t WORD_BOUNDARY b iː WORD_BOUNDARY t ɹ uː WORD_BOUNDARY ʌ WORD_BOUNDARY l aɪ WORD_BOUNDARY k æ n ɑ t WORD_BOUNDARY ɔ l s oʊ WORD_BOUNDARY b iː WORD_BOUNDARY ʌ WORD_BOUNDARY t ɹ uː θ WORD_BOUNDARY s oʊ WORD_BOUNDARY ð ə WORD_BOUNDARY s ɛ n t ə n s WORD_BOUNDARY b iː ɪ ŋ WORD_BOUNDARY t ɹ uː WORD_BOUNDARY m eɪ k s WORD_BOUNDARY ɪ t WORD_BOUNDARY ʌ WORD_BOUNDARY l aɪ WORD_BOUNDARY