元気[げんき]ではありません。(“gen-ki de-wa-a-ri-ma-sen.”; “I’m not fine”)
~です(de-su), as mentioned previously, is the standard polite way to end a sentence affirmatively (like a period you speak aloud).
~ではありません(de-wa-a-ri-ma-sen) is the standard polite way to make a sentence negative.
*NOTE* if you can read hiragana, you will notice that the second character は is pronounced as “wa” this time instead of “ha”, as mentioned in a previous post. We are using the は character as the particle indicating “is/are”, and for now, think of ありません(a-ri-ma-sen) as meaning “is not”.