You’re doing something wrong.
Unsubscribing from a newsletter should be painless and straightforward. If you need as much text as in the example below, your design is confusing.
I know – it’s tempting to want to clarify your UI with text, to make what the user needs to do explicitly clear. However, the more text you need to describe the intended action, the less inherently intuitive your design. If it were intuitive, why would it need explicit, detailed instructions?
Also, keep in mind that users tend to scan, not read. As such, your elaborate instructions and guidance are wasted. Squint your eyes until the text becomes blurry. How obvious is it what the user should do?
In the example above, it’s not at all clear without reading the text. Should the user check or uncheck the the box before clicking the yellow button? This is crucial to the user achieving his goal – presumably, to unsubscribe, since that’s how he (well, I) got to this page – and 50/50 odds are unacceptable.
The moral of this story is not that you should resist the urge to add clarifying text. Rather, the moral is to recognize that urge as an indication that your UI isn’t as intuitive as it could be. Revisit it. Squint at it. Strive to make it so obvious and fool proof that you don’t need much text at all.