Song lyrics, say Justin Beiber's Baby ?
Write whatever makes you feel nice instead of shining in borrowed plume?
To write such texts, it is important to have a good vocabulary, in my opinion. I am a student and I know how difficult it is to write inspirational texts and select the necessary words. I suggest you pay attention to the expert guide to writing academic texts https://www.netlingo.com/tips/how-to-become-successful-in-academic-essay-writing.php. This will greatly simplify your process of writing a love letter. Write from the heart.