Words ending with tsade are not uncommon. Land or earth is present with us even as a 'borrowed' word in English in the phrase 'eretz Israel'. This letter has a formative potential in the sound of the story. It is repeated in some significant words. The anticipation of the 'ts' is in chapter 1, but it is the major sound of chapter 2 and after the first few verses of chapter 3 it ceases till the mention of Perez in chapter 4. I have not heard this in any reading I have heard but I am convinced it should be there. The reading at Mechon-Mamre is a little too monochromatic for my taste. Maybe some day I will record it in Hebrew. (but not for a while I assure you)
Here is the trailing 'ts' in the first verse, Ruth 1:1. I will leave the greening of the grammatical letters to you.
Ruth 3:13 has the letter again in an allegorically significant word. When we get back to real story, we will hear it.
also 3 times in the proper name פָּרֶץ
There is only one word beginning with tsade in Ruth
Used again in Ruth 3:6
There are a number of words that contain the sound, some of them key repetitions or concepts in the tale.
Ruth 1:7, 1:13, 2:18, 2:22 come out
Then the sound stops till we find it in proper names in the middle and at the end.