I don’t speak a lick of Japanese but I found this online:

です is used to mark words as polite if they cannot conjugate to show politeness themselves… です is one of the most fundamental words in the Japanese language. It’s super useful — it can be attached to just one other word to form some basic sentences. It’s also quite safe to use since it’s part of the polite form, so you’re unlikely to offend someone with this word… です can be tacked onto the end of a noun, な-adjective, or い-adjective to form a polite, positive, present tense sentence (say that ten times fast 😉). In other words, it allows us to talk about something that is true, and relevant to the present moment and/or the future—all in a polite way of course.

source: https://www.tofugu.com/japanese-grammar/desu/

While the other answer is correct and more comprehensive, in this phrase the particles are purely used to make the phrase “polite”. Take them out and the phrase is semantically correct and has the exact same meaning, but it can now only be used in an informal settings (between friends, family, …)

Disclaimer: I have only basic knowledge of Japanese, and my Japanese teacher would enthusiastically confirm.

That’s a tricky one. I guess it sort of means “it is that” if you take it super literally? “It is that I want to try on the suit.” But in practice, it just adds a level of politeness and formality to the sentence.

You will hear a lot of masu (ます) and desu (です) tossed in there all over the place when people are trying to be courteous.