I am curious if starting a new sentence right before a new line, in this case leaving only one word before the new line, is correct. I am having trouble explaining even what this situation is, but I am wondering if this is correct or if I should change the sentence. Thank you!
Sentence structure is independent of document layout.
The esthetics of how a document looks is a function of typesetting and is a publisher's prerogative. The writer need not concern themselves with that aspect of production.
For most writers, the question is does this sentence belong in this paragraph. I expect that poetry might could deviate from that rule, but poets don't worry about paragraphs and sentences anyway, in a rigid way.
You may find the look of your paragraphs unpleasing, at times, but as was stated before that is aesthetics and not an element of the craft of writing. Modern word processing programs like MS Word or Google Docs use pagination algorithms to decide where a soft line break occurs. If the writer is using hard line breaks to force a pagination, that will pretty much bring anguish and annoyance later since edits above that line can change the pagination forcing the writer to review the entire document and fix their previous fixes.