premise: A man talking to a woman while he is holding her arm on a street at night. hypothesis: a man and a women are holding hands at night.
entailment: The second sentence is inferring affection, vaguely using the details provided in sentence one. Her hand is on her arm, so it's possible, though not said. The man is holding the woman but while a hand is part of an arm, that was not mentioned in the first sentence.