If you want to say yes in German, the right word to use is "ja." However, as simple as this word looks, you might confuse a lot of German speakers if you decide to pronounce the word as "jar." The pronunciation of this word is not the same as it looks. Most times, the letter "J" in German is pronounced as the letter "Y."
So, if you want to say pronounce the German word "ja," you can pronounce it like when you want to say, "Yah." With this, you won't have any problem communicating your mind to other German speakers around you.
At times, the word "ja" can be used together with another German word "bitte," which means, please. So, when you use them together, it means "yes, please." The German word bitte is pronounced as (BIH-tuh). Just as there are other words or phrases you can use in English to convey the exact meaning as "yes," this also exists in German. Germans also use "okay" to replace the word "yes."