How can I know what xpath class contains?

.//*[@id='contentText']/table/tbody/tr[2]/td/table/tbody/tr/td[1]/table/tbody/tr[10]/td/table/tbody/tr/td[1]/strong[2]
That XPath class contains should be drastically shortened. That is likely to fail if you are testing in different browsers and if anything ever changes on the page it could throw a false positive due to it looking at the wrong element. I recommend looking up "Relative XPaths" and also "XPath Axes", but I could demonstrate a better XPath for you if you posted a screenshot of the HTML and the web page.
Based on what you posted, you could do something like: //table[@id ='something' or @class='Something that identifies this specific table']//tr[contains(text(), 'something to identify the row') or ./text() = 'Exact Text Match']//strong[2]
Usually with table rows I end up identifying the row based on the text from a cell within the row. //table[@id ='something' or @class='Something that identifies this specific table']//tr[.//td[contains(text(), 'something to identify the row') or ./text() = 'Exact Text Match']]//td//strong[2][contains(text(), 'Partial Text Match') or ./text() = 'Exact Text Match']