Ravi Kumar, 27, was jailed for molesting the 27-year-old woman in Redhill housing estate on the night of September 9, The Straits Times reported.
Ravi Kumar was drinking beer with his friend when he saw the victim at Block 84, Redhill Lane, and struck up a conversation with her. The victim was with her elder sister, who was talking on her cellphone.
Shortly after, Ravi Kumar stood up and gave 10 dollars to the victim's sister and told her to "buy drinks".
The victim scolded him and called the police.