Every other translation I checked says "grace" where the NWT says "Undeserved kindness".
It reads so much clunkier that way...the other way is so...graceful if you will.
I looked at the kingdom interlinear and they have "χάρις, ιτος, ἡ" translated undeserved kindness.
Strongs says...
charis: grace, kindnessOriginal Word: χάρις, ιτος, ἡPart of Speech: Noun, Feminine
Transliteration: charis
Phonetic Spelling: (khar'-ece)
Short Definition: grace, favor, kindness
Definition: (a) grace, as a gift or blessing brought to man by Jesus Christ, (b) favor, (c) gratitude, thanks, (d) a favor, kindness.
I don't see "undeserved" anywhere.