How to send order confirmation email after placing order using rest API?

I am using following code to create order using rest API.

$apiURL="https://domain.com/index.php/rest/V1/carts/mine/payment-information";
$data_string =json_encode(array("paymentMethod"=>array("method"=>"banktransfer"),"billing_address"=>array("customer_id"=>100,"region"=>"Test Region","region_id"=>25,"country_id"=>"US","telephone"=>"1234567890","postcode"=>06401,"street"=>array("0"=>"testing"),"city"=>"testing","firstname"=>"John","lastname"=>"Doe","region_code"=>"NV")));
$ch = curl_init($apiURL);
curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "POST");
curl_setopt($ch, CURLOPT_POSTFIELDS, $data_string);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, array("Authorization: Bearer ".$token,"Content-Type: application/json"));

Order is created but no email is sent. In admin section “The order confirmation email is not sent” is displayed.