There are only so many ways to express each of those ideas. The simplest way to express the first value above is "work hard for what you want." "Work hard" is simpler but not quite complete. It can be modified and/or embellished, for example, "work hard for what you are passionate about" or "work hard for what you want in life" but there's really not that many different ways to convey that particular idea and keep it simple, short and concise.
So I'm more than a little surprised that Melania Trump is being accused of plagiarizing a speech many years ago by Michele Obama. Here are the two most similar (nearly identical) excerpts (non-matching punctuation removed by me in each since they were delivered verbally):
"...values that you work hard for what you want in life, that your word is your bond and you do what you say..." Michelle Obama, 2008
"...values that you work hard for what you want in life, that your word is your bond and you do what you say..." Melania Trump, 2016That's not that long of a string of words discussing nearly universally held values with not all that many ways to say them in a speech where brevity and conciseness is important. I've certainly personally said or written "work hard for what you want in life" and "you do what you say" many, many times. Much of the rest of the wording is connectors (like "and," "that" and so forth). I personally wouldn't say "your word is your bond" because that's not my style but I'm certain that Michelle Obama is NOT the first person to coin that phrase and I've heard it many, many times as well.
There are two possibilities. One is that those 23 words are one of the most effective ways to convey those particular values in a speech and, as a result, Obama and Trump happened to use the same words. The other is that Melania Trump and supporting speechwriters pored through Michelle Obama speeches and deliberately copied those 23 words. Perhaps there are other possibilities as well, but I think those are the most likely.
Of those two possibilities, the first seems far, far more likely to me. As I write this, I think "they" are still investigating, so I'm curious as to what the final outcome is.
But if that is considered plagiarism, I'm certain that many of the one to two dozen word strings I've written in this blog (and elsewhere) certainly match something somebody else somewhere sometime has written. In which case you can look down your nose at me as a lowly plagiarist too! Sorry, we can't all be perfectly original all of the time.