There is a special helper for comments. Everything inside is not sent to the client and is not included in the final text.

You just need to wrap the text in {{!-- and --}}:

{{!-- this text will not be shown --}}
And this text will be shown

Comments are useful if you have large texts with helpers and you do not want to get confused:

{{!-- if the balance minus the rate value is greater than zero --}}
{{#gte (subtract balance cost) 0}}
{{!-- then we'll tell you about it --}}
Great, you have enough money to buy this course
{{!-- but if not, then we will ask you to top up the balance --}}
It seems that there is not enough money in your account to buy the course
Top up the balance by the link