app.intent('sendMail', (conv, params) => {

  const nodemailer = require('nodemailer');
  const transporter = nodemailer.createTransport({
    service: 'gmail',
    auth: {
      user: 'mymail',
      pass: 'mypass'
    }
  });

  var mailOptions = {
    from: 'mymaill',
    to: 'mymail', //receiver email
    subject: 'Mail subject',
    text: 'mail body'
  };

  transporter.sendMail(mailOptions, function (error, info) {
    if (error) {
      console.log(error);
    } else {
      console.log('Email sent: ' + info.response);
    }
  });