So, this is what you do:
You give the name and gender of the person you want to send the letter. Add your own name and gender, plus click whether you want the letter to be cautious (zaghaft), normal (normal) or passionate (stürmisch), also whether it should be short (kurz), medium size (mittel) or long (lange).
On the right, you add from the dropdown menu the colour of his/ her eyes and hair and special features and what you would like to do. Then press ‘Liebesbrief generieren’!
I tried out a short, cautious one and got this:
A long, passionate one may look like this:
Could there be a better way to practise some German? I think not 🙂