<!DOCTYPE html>
<html lang="ja">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>a {
  display: inline-block;
  text-decoration: none;
  color: #FFF;
  font-weight: bold;
  text-align: center;
  margin: 10px;
  width: 160px;
  padding: 0.5em 2em;
}
span{
  color: #FF3399;
}
.btn{
  position: relative;
  height: 50px;
  line-height: 50px;
  background-image: linear-gradient(45deg, #ffafbd 0%, #ffc3a0 100%);
  transition: .4s;
  padding: 0;
}
.btn:before {
  position: absolute;
  content: '';
  left: 0;
  top: 0;
  width: 0;
  height: 0;
  border: none;
  border-left: solid 21px white;
  border-bottom: solid 51px transparent;
  z-index: 1;
  transition: .4s;
}
.btn:after {
  position: absolute;
  content: '';
  right: 0;
  top: 0;
  width: 0;
  height: 0;
  border: none;
  border-left: solid 21px transparent;
  border-bottom: solid 51px white;
  z-index: 1;
  transition: .4s;
}</style>
</head>
<body>
<a class="btn" href="#">お し て <span>&#9829;</span>
</a>
<script>
</script>
</body>
</html>
a {
  display: inline-block;
  text-decoration: none;
  color: #FFF;
  font-weight: bold;
  text-align: center;
  margin: 10px;
  width: 160px;
  padding: 0.5em 2em;
}
span{
  color: #FF3399;
}
.btn{
  position: relative;
  height: 50px;
  line-height: 50px;
  background-image: linear-gradient(45deg, #ffafbd 0%, #ffc3a0 100%);
  transition: .4s;
  padding: 0;
}
.btn:before {
  position: absolute;
  content: '';
  left: 0;
  top: 0;
  width: 0;
  height: 0;
  border: none;
  border-left: solid 21px white;
  border-bottom: solid 51px transparent;
  z-index: 1;
  transition: .4s;
}
.btn:after {
  position: absolute;
  content: '';
  right: 0;
  top: 0;
  width: 0;
  height: 0;
  border: none;
  border-left: solid 21px transparent;
  border-bottom: solid 51px white;
  z-index: 1;
  transition: .4s;
}