But a benevolent ruler, like Liu Bei, often garner the trust and respect of others

they were often easyer to kill or atleast be beaten.

how many times was liu bei beaten and needed to start over again?
atleast 3 times from what i recall. every time he settled and had people around him. he was beaten again and driven off the country.

By now, you should all know what it's like to be feared and loved, since you all became famous princes and princesses and stuff.

I prefer to be loved, but that's just a personal preference. I don't want to be feared.

Ah, a famous saying by Niccolo Machiavelli

Whether or not a prince should be loved or feared

If the prince would be feared, he would be hated. You would not like to be hated.
If a prince was to be loved, the people will not take the prince seriously. That will lead to the destruction of his kingdom.

Which is better, loved by many of feared by all?

Honestly, in terms of power, feared by all. Love is fleeting, and not all will love you, but fear? That's a different matter all together...

Ah, a famous saying by Niccolo Machiavelli

Whether or not a prince should be loved or feared

If the prince would be feared, he would be hated. You would not like to be hated.
If a prince was to be loved, the people will not take the prince seriously. That will lead to the destruction of his kingdom.

Actually a very good point there.

how many times was liu bei beaten and needed to start over again?
atleast 3 times from what i recall

This was not due to him being a loved/weak ruler...but because during those times he didn't have much resources. He started with almost literally nothing.
Also, each time he was defeated he was able to find a new place of refuge...why? Because he was beloved and respected.

they were often easyer to kill or atleast be beaten.

Not necessarily true, especially for the time period of the Three Kingdom era we are all focusing on

Once Liu Bei was able to establish himself in Shu, he became nearly unbeatable for some time. The Sun family also kept their strong positioning and they were loved by their people

Then we have Dong Zhou, who was very much hated and taken down very swiftly.  Lu Bu was hated and had many enemies. Yuan Shu

But some rulers that were easily defeated didn't have that result because of their kindness...but because they just weren't sufficient rulers. Liu Shan was a kind ruler, he also was an inept one. It was due to him being inept that caused Shu Han to fall, not his kindness.
At the same time, Lu Bu was a ruler who ruled with fear, but he was also a very arrogant and aggressive ruler. It was due to his arrogance and aggression that caused him to be defeated so easily

It's best to rule with love, but not be timid.

You're doing something wrong if the people are scared. Just because people aren't cowed into following doesn't mean there is no security.

Also, each time he was defeated he was able to find a new place of refuge...why? Because he was beloved and respected.

he could just as easly be slain at one of his defeats. but instead he fleet the battle.
a mad man would also find refuge if he was spared in battle or if he fleet.

Once Liu Bei was able to establish himself in Shu, he became nearly unbeatable for some time.

but he wasn't the ruler.
a good captain doesn't make it a good leader.

Then we have Dong Zhou, who was very much hated and taken down very swiftly.

wasn't dong zhou self proclaimed king for over 20 year befor the 3 kingdoms era?

but he wasn't the ruler.
a good captain doesn't make it a good leader.

my bad i mixed up the armys.

but still his shu was defeated multiple times.

It's best to rule with both love and fear. And neither be a ruler of just one way. But love is a necessity to have in a kingdom.
The Three Kingdoms Era in China is a bit a weird one, partly because it was just a period of so much strife and turmoil. Whether or not a ruler went up or came down truly depended on how loyal their armies and captains were to them. But it also points out that a ruler can be benevolent and loving and still be a successful prince.
Fear mainly applies to people outside of the nation. Love is necessary to show the people what they have to gain if they remain loyal, and also makes them feel a part of something. If you wish to remain successful, you have to be loved first, and then you can give your enemies something to be feared of. But if you rule with fear, and then try to show love to the people, that just doesn't really work. No one can forget an injustice or an act of ruthlessness.