In attachment view, HTML title attribute is as tool tip, so when you verify it, just get the attribute of the title .
In other view, like following, it is coded by EXT component. So when you verify this, you may need to get the element of the tool tip
Here’s an article for this
https://www.seleniumeasy.com/selenium-tutorials/how-to-verify-tooltip-text-with-selenium-webdriver-using-java