Here's some notes from my lifetime as a fan.
1980-1982, DePaul is a #1 seed all 3 years, the #1 ranked team in the country going into the tournament in 80 and 81. They lose in the second round (their first game, because that was back when there were byes) 3 straight years.
1983- Houston, huge favorite, #1 most of the year, loses to NC State in the final.
1984- UNC has a junior Michael Jordan, senior Sam Perkins, sophomore Brad Daugherty, and freshman Kenny Smith. #1 most of the year. They lose in the Sweet 16.
1985- Georgetown is defending champ, only loses twice all year, generally dominates. They lose in the final to Villanova.
1986- Duke is #1 most of the year. They lose in the final
1987- UNLV goes into the FF the favorite. They lose in the semis.
1988- Arizona spends most of the year at #1. They lose in the semis to a very strong Oklahoma team, which then loses in the finals to Kansas.
1989- Illinois goes into the FF the favorite. They lose in the semis.
1991- UNLV is undefeated going into the semis, mostly dominant. They lose.
1992- Duke manages a repeat, but only with a miracle win that we're all very familiar with.
1994. UNC goes into the tourney pretty much co-favorite with Arkansas. They lose in the 2nd round.
1997. Kansas spends almost all year at #1, loses 1 game. They bow out in the Sweet 16.
1998. Arizona, UNC, Duke, and Kansas spend almost all year as the top 4. None win the title, only 1 makes the FF.
1999. Duke enters the FF having won over 30 games in a row, mostly dominating opponents. They lose in the final.
2000- 2 one seeds lose in the first round, another in the Sweet 16.
2002- Duke goes into the tournament the favorite. They lose in the Sweet 16.
2003- UK/Marquette
2006- UConn is considered the favorite. They lose to George Mason in the Elite 8.
The rest is pretty much recent history. And the point is, if you want certainty, you're watching the wrong sport.