No. You won’t be able to redeem Singapore Airlines miles for cash. The miles can be redeemed for award tickets, upgrade awards and other redemption options on Singapore Airlines.
If you want to be able to redeem for flights and cash, consider getting a travel rewards credit card. For example, it can be the Discover it® Miles credit card. It allows to earn 1.5 miles per dollar on all purchases. The miles you earn your first year, will be matched at the end of the year (provided you are a new cardmember). Earned miles can be redeemed as travel statement credits or as cash deposited to your account. When redeeming for travel statement credits, you can cover the cost of any airline ticket with miles. The card has no annual fee and no foreign transaction fees.