There are event you can predict on that even though it's not 💯 guaranteed that you're going to win, a level of certainty makes you think that you're surely going to win.
The downside of that feeling is that you might become over confident to use a big amount in the game since you're to a large extent certain that you're going to win.
Can we still say we are gambling if the event is something we are at least 90% sure that we are going to win?
As long as it's not 100%, it's still gambling. Even it's 99% chance that you're winning, there's still 1% chance that you're not. I've played MMORPG games for a long time already that's why even a 1% chance or even lower still matters - just like in those games where the drop rate is below 1%. I also apply it on gambling.
For me, as long as it's not 100%, I don't want to say that you're "guaranteed" to win. There's no such thing as certainty when it comes to gambling or even in investing. 90% chance of winning can still make you lose your money. I mean there's still 1 out of 10 chances that you will lose your money, and that's still a huge one. For me, there's no such thing as "sure win" in gambling despite the low odds or in this case, 90% chance of winning.