Existence is suffering. Cessation of existence is a realization of the truth of the cessation of suffering.
“Just as, mendicants, even a tiny bit of fecal matter still stinks, so too I don’t approve of even a tiny bit of continued existence, not even as long as a finger snap.” AN1.329
“One perception arose and another perception ceased in me: ‘The cessation of existence is nibbāna; the cessation of existence is nibbāna.’ Just as, when a fire of twigs is burning, one flame arises and another flame ceases, so one perception arose and another perception ceased in me: ‘The cessation of existence is nibbāna; the cessation of existence is nibbāna.’ On that occasion, friend, I was percipient: ‘The cessation of existence is nibbāna.’” AN10.7
When you say;
the cycle of birth and death produces suffering but ,once the truth is realized suffering has no power ,so living in this world shouldn't be any longer a problem.
You are slipping by the definition of suffering as all conditioned phenomena;
Monks, there are these three kinds of suffering.[1] What three? Suffering caused by pain,[2] suffering caused by the formations (or conditioned existence),[3] suffering due to change.[4] It is for the full comprehension, clear understanding, ending and abandonment of these three forms of suffering that the Noble Eightfold Path is to be cultivated..." SN45.165
Even the existence of what can be grasped with wrong view to be an Arahant or personal and belonging to an Arahant, that is classed as suffering.
The Arahants are disenchanted with suffering and thus with the breakup of the body do not take up another body and their consciousness does not become established in any sphere of existence, they abandon all being;
These two Nibbāna-elements were made known
By the Seeing One, stable and unattached:
One is the element seen here and now
With residue, but with the cord of being destroyed;
The other, having no residue for the future,
Is that wherein all modes of being utterly cease.
Having understood the unconditioned state,
Released in mind with the cord of being destroyed,
They have attained to the Dhamma-essence.
Delighting in the destruction (of craving),
Those stable ones have abandoned all being. Iti44
Existence is a truth and it's cessation is also a true principle to be realized and when known as it actually is, it is known to be the highest bliss also called Asoka [Sorrowless] state.
It's hard to see the unaffected,
for the truth is not easily seen.
Craving is pierced
in one who knows;
For one who sees,
there is nothing. Ud8.2
Cessation of the conditioned depends on the unconditioned element, if there was no unconditioned then the cessation principle wouldn't be possible.
There is that dimension, monks, where there is neither earth, nor water, nor fire, nor wind; neither dimension of the infinitude of space, nor dimension of the infinitude of consciousness, nor dimension of nothingness, nor dimension of neither perception nor non-perception; neither this world, nor the next world, nor sun, nor moon. And there, I say, there is neither coming, nor going, nor staying; neither passing away nor arising: unestablished,[1] unevolving, without support .[2] This, just this, is the end of stress. Ud8.1
There is, monks, an unborn — unbecome — unmade — unfabricated. If there were not that unborn — unbecome — unmade — unfabricated, there would not be the case that escape from the born — become — made — fabricated would be discerned. But precisely because there is an unborn — unbecome — unmade — unfabricated, escape from the born — become — made — fabricated is discerned. [Ud8.3] (https://www.accesstoinsight.org/tipitaka/kn/ud/ud.8.03.than.html)
When cessation principle is realized it is known as pleasant and any existence in the light of it is categorically known as suffering.
It is as if a tired person was offered a seat just to have that seat pulled out from underneath him, not knowing better, might think; 'This good person is offering me a seat out of kindness, why don't i accept?'. So he accepts, time and again, not understanding as it actually is, that it is out of cruelty and for the purpose of suffering that he is offered a seat.
If later the tired person the was offered a stable relief then he would discern the cruelty in what was previously offered and if offered to take a seat would pass on the offer, discerning the deal as suffering.
Therefore the mind of one who has realized the cessation principle realizes the truth of suffering, the truth of arising of suffering, the truth of it's cessation & the path to the cessation; and thus inclines to Nibbana which is the utter extinguishment of the conditioned & of the causes which beget the conditioned existence.
There he said to the monks, "This Unbinding is pleasant, friends. This Unbinding is pleasant."
When this was said, Ven. Udayin said to Ven. Sariputta, "But what is the pleasure here, my friend, where there is nothing felt?"
"Just that is the pleasure here, my friend: where there is nothing felt. AN9.34
Now it's possible, Ananda, that some wanderers of other persuasions might say, 'Gotama the contemplative speaks of the cessation of perception & feeling and yet describes it as pleasure. What is this? How can this be?' When they say that, they are to be told, 'It's not the case, friends, that the Blessed One describes only pleasant feeling as included under pleasure. Wherever pleasure is found, in whatever terms, the Blessed One describes it as pleasure.'" MN59
