Form with acceptance validation

_form.html.erb

<%= form_with(model: account, local: true) do |form| %>
  <%= form.govuk_error_summary %>

  <%= form.govuk_email_field(:email) %>

  <%= form.govuk_check_boxes_fieldset :terms_and_conditions,
    legend: { text: 'Please accept our terms and conditions' } do %>

    <%= form.hidden_field :terms_and_conditions, value: false %>
    <%= form.govuk_check_box :terms_and_conditions, true, multiple: false, link_errors: true %>
  <% end %>

  <%= form.govuk_submit %>
<% end %>

account.rb

class Account < ApplicationRecord
  validates :email, presence: true
  validates :terms_and_conditions, acceptance: { accept: true }
end