How to escape HTML code inside an attribute of type data-text?

I wrote the following code:

<label class="form-input">
                <i class="material-icons"><span class="glyphicon glyphicon-lock" aria-hidden="true"></span></i>
                <input class="password-mask input-popover"
                       type="password"
                       autocomplete="off"
                       id="NewPassword"
                       maxlength="16"
                       name="NewPassword"
                       required
                       onchange="VerifyInput('NewPassword', 'newPassword-text'); this.setCustomValidity('');"
                       oninvalid="this.setCustomValidity('Por favor, preencha este campo.')"
                       onkeyup="CalculeStrength('NewPassword', 'strengt-bar', 'strengt-label')"
                       title=" "
                       data-toggle="popover"
                       data-html="true"
                       data-content="<div><p>Digite ao menos uma letra</p></div>"
                       data-container="body"
                       data-trigger="focus" />
                <span id="newPassword-text" class="label">Nova senha</span>
                <span class="underline"></span>
            </label>

The problem is that within the 'data-content' attribute I need to insert a code in HTML which will then be formatted via CSS.

I'm using visual studio and it's not escaping '/'.

How can I escape the '/'?