Descent and dissent are easily confused words.
The spell-check application of most word processing software programs would not catch a slip-up of these two words. Spell-check is looking for words that aren’t in its dictionary, and words that resemble words in its dictionary but are possibly spelled wrong. Spell-check isn’t perfect. It doesn’t know and can’t guess what word you wanted or what word you meant, it can only judge the words on the page. If you used words that are all spelled correctly, it gives you a pass anyway.
Autocorrect suggests words that start with the same letters. It suggests what word you may want to save time, but quite often, its suggestions couldn’t be more off base and produces humorous results.
Descent is a noun form of the verb descend. Descent means heading on a downward path or trajectory, or to be in a state of decline.
Dissent has multiple forms. Dissent is a verb meaning to disagree, or differ in opinion. The noun form, is the different opinion. When the Supreme Court makes a decision, typically there is a majority opinion which determines what the decision is. But for those judges in the minority that disagreed, one is chosen to write the “dissenting” opinion.
The following story uses both words correctly:
Desmond had a successful political career for years, but the tide seemed to be turning. When he expressed his dissenting opinion about the strengths of common core, his approval numbers experienced a notable descent.