"Unfortunately, there is no sea close to my city."
Translation:لِلْأَسَف لَيْسَ هُناك بَحْر قَريب مِن مَدينَتي.
(1) In the sentence above, هناك is what we call it in English as the predicate (yes, I know the English logic is not 100% the same with Arabic -- or English is different a lot).
(2) Yes, your sentence is correct!
ليس البحر عميقاً ... هذه الجملةصحيح
(3) You're welcome :)) ❤️❤️