The reason this looks odd is because, in English, the conclusion acts like appositive (not to mention sentence fragment). toki pona does not have any appositives, plus a sentence fragment violates the strict sentence rules. I suggest we end our letter with a simple sentence that makes clear who is the speaker by giving the speaker's name, while also adding that the speaker is the recipient's friend:jan pona sina,
jan Tomaniki
Perhaps a short additional sentence (pona!) could be used to finalize the letter. Saying "I am your friend and Dominick" might be confused for being a new body paragraph. However, being convention, the unusual way we express it will be justified in that there is no other way to say it. A modern English-speaker would probably think it would be odd if someone used the word "sincerely" in everyday conversation; however the word does not seem odd in even informal letters because we are so used to it.mi jan pona sina li jan Tomaniki.
sina pilin seme?