How to get error message after entity validation

I'm trying to get a clean error message after validating my Subscribe Entity :

/**
 * Subscribe
 * @UniqueEntity("email")
 * @ORM\Table(name="subscribe")
 * @ORM\Entity(repositoryClass="AppBundle\Repository\SubscribeRepository")
 */
class Subscribe
{
    /**
     * @var int
     *
     * @ORM\Column(name="id", type="integer")
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="AUTO")
     */
    private $id;

    /**
     * @var string
     * @Assert\NotBlank()
     * @Assert\Email()
     * @ORM\Column(name="email", type="string", length=255, nullable=true, unique=true)
     */
    private $email;

After calling the validator service and test it with blank email:

   $validator = $this->get('validator');
   $errors = $validator->validate($email);
    if (count($errors) >0) {
    return new JsonResponse( (string)$errors);
      }

I got this message Object(AppBundle\Entity\Subscribe).email: This value must not be empty. (code c1051bb4-d103-4f74-8988-acbcafc7fdc3). Any idea how to clean it ?