user5315: My understanding is that, although we are practicing five precepts in this life, there is no guarantee we will not be reborn in lower realm, it is possible to take rebirth in lower realm in the next life or many lives after. But according some sources, when one practices five precepts that person will not be reborn in one of the lower realms (in the next life). Which one is the correct one?

user471: There are many levels of achievement in Theravada Buddhism (in ascending order):

Faith follower
Dhamma follower
Stream enterer
Once returner
Non-returner
Arahant

The faith follower basically has faith and conviction in the Buddha as the teacher of the path to the end of suffering, the Dhamma (teachings of the Buddha) and the Sangha (the 8 types of individuals on the path). The faith follower would normally take refuge in the Buddha, Dhamma and Sangha, as well as vow to undertake the five precepts. That's merely the first step.
The guarantee of not being reborn in lower realms (hell, animal, asuras and hungry shades) is the result of achieving stream entry (or higher).
For all others, there is no guarantee.
According to the Vera Sutta:

"When, for a disciple of the noble ones, these five forms of fear &
  animosity are stilled; when he is endowed with these four factors of
  stream-entry; and when, through discernment, he has rightly seen &
  rightly ferreted out this noble method, then if he wants he may state
  about himself: 'Hell is ended; animal wombs are ended; the state of
  the hungry shades is ended; states of deprivation, destitution, the
  bad bourns are ended! I am a stream-winner, steadfast, never again
  destined for states of woe, headed for self-awakening!'"

The five forms of fear and animosity are stilled by the relentless practice of the five precepts.
The four factors of stream-entry are verified confidence in the Buddha, the Dhamma, the Sangha, and having "virtues that are appealing to the noble ones: untorn, unbroken, unspotted, unsplattered, liberating, praised by the wise, untarnished, leading to concentration."
The noble method is the understanding of how suffering is ended by the realization of dependent origination.
The one who has fulfilled the above, becomes a stream winner, who is guaranteed freedom from rebirth in lower realms.

user111: Reaching at least the Sotapanna state is the only 100% guarantee of not being born in lower realms ever again.
But if you reach at least the second insight knowledge -Paccaya Pariggaha Nana of the 16 stages of insight towards becoming a Sotappanna, it is said that you will not be born in a lower realm in the immediate next life.
If you are a devout Buddhist who keeps to the five precepts, it is highly unlikely to be born in a lower realm in the next life. But there's no guarantee. It mostly depends on the quality of your precepts. As in how well you keep to them.

5315: <p>My understanding is that, although we are practicing five precepts in this life, there is no guarantee we will not be reborn in lower realm, it is possible to take rebirth in lower realm in the next life or many lives after. But according some sources, when one practices five precepts that person will not be reborn in one of the lower realms (in the next life). Which one is the correct one?</p>
 471: <p>There are many levels of achievement in Theravada Buddhism (in ascending order):</p>

<ul>
<li>Faith follower</li>
<li>Dhamma follower</li>
<li>Stream enterer</li>
<li>Once returner</li>
<li>Non-returner</li>
<li>Arahant</li>
</ul>

<p>The faith follower basically has faith and conviction in the Buddha as the teacher of the path to the end of suffering, the Dhamma (teachings of the Buddha) and the Sangha (the 8 types of individuals on the path). The faith follower would normally take refuge in the Buddha, Dhamma and Sangha, as well as vow to undertake <a href="https://www.accesstoinsight.org/ptf/dhamma/sila/pancasila.html" rel="nofollow noreferrer">the five precepts</a>. That's merely the first step.</p>

<p>The guarantee of not being reborn in lower realms (hell, animal, asuras and hungry shades) is the result of achieving <a href="https://www.accesstoinsight.org/lib/study/into_the_stream.html" rel="nofollow noreferrer">stream entry</a> (or higher).</p>

<p>For all others, there is no guarantee.</p>

<p>According to the <a href="https://www.accesstoinsight.org/tipitaka/an/an10/an10.092.than.html" rel="nofollow noreferrer">Vera Sutta</a>:</p>

<blockquote>
  <p>"When, for a disciple of the noble ones, these five forms of fear &amp;
  animosity are stilled; when he is endowed with these four factors of
  stream-entry; and when, through discernment, he has rightly seen &amp;
  rightly ferreted out this noble method, then if he wants he may state
  about himself: 'Hell is ended; animal wombs are ended; the state of
  the hungry shades is ended; states of deprivation, destitution, the
  bad bourns are ended! I am a stream-winner, steadfast, never again
  destined for states of woe, headed for self-awakening!'"</p>
</blockquote>

<p>The five forms of fear and animosity are stilled by the relentless practice of the five precepts.</p>

<p>The four factors of stream-entry are verified confidence in the Buddha, the Dhamma, the Sangha, and having "virtues that are appealing to the noble ones: untorn, unbroken, unspotted, unsplattered, liberating, praised by the wise, untarnished, leading to concentration."</p>

<p>The noble method is the understanding of how suffering is ended by the realization of <a href="https://buddhism.stackexchange.com/q/48/471">dependent origination</a>.</p>

<p>The one who has fulfilled the above, becomes a stream winner, who is guaranteed freedom from rebirth in lower realms.</p>
 111: <p>Reaching at least the Sotapanna state is the only 100% guarantee of not being born in lower realms ever again.</p>

<p>But if you reach at least the second insight knowledge -<strong><em>Paccaya Pariggaha Nana</em></strong> of the 16 stages of insight towards becoming a Sotappanna, it is said that you will not be born in a lower realm in the immediate next life.</p>

<p>If you are a devout Buddhist who keeps to the five precepts, it is highly unlikely to be born in a lower realm in the next life. But there's no guarantee. It mostly depends on the quality of your precepts. As in how well you keep to them.</p>
