In dependent origination, 'jati' ('birth') refers to the conception & production of the view of 'beings' ('satta') based in the beguiling appearance & manifestations of various aggregates and the mind seized by & enslaved to sense objects (ayatana).
Comprehending 're-birth' is therefore necessary to understand the Buddha's message & to reach enlightenment.
The Buddha did not teach the two truths doctrine. The defiled/polluted mundane right view in MN 117 is not really 'the truth' because it is defiled with upadhi (attachment;self-views). It is only a right view that accords with morality (rather than accords with Nibbana).
'The two truths' were developed a little later on by Buddhaghosa. However, again the two truths of Buddhaghosa are not really both truth because one truth is how the truth really is and the other truth is the worldly interpretation by the unenlightened. Buddhaghosa said:
The Awakened One, best of speakers, Spoke two kinds of truths: The conventional and the ultimate. A third truth does not obtain.
Therein: The speech wherewith the world converses is true On account of its being agreed upon by the world. The speech which
describes what is ultimate is also true, Through characterizing
dhammas as they really are.
Therefore, being skilled in common usage, False speech does not arise in the Teacher, Who is Lord of the World, When he speaks
according to conventions.
(Mn. i. 95)
In the language of ultimate truth, since 'rebirth' simply means the re-arising of 'self-view', it is an ultimate truth because this is how suffering always occurs.
'Re-birth' or 'new-birth' is conditioned by new or re-becoming, as explained in dependent origination.
This re-birth will inevitably result in 'death' ('marana'); that is, the painful sense the born 'self' or 'self-identity' has lost something; or otherwise the sense that other 'beings' ('satta') have also lost something.
When the lesson of marana & resultant dukkha is not learned, ego birth will occur again in the mind, which is re-rebirth.
Rebirth is a reality that can be affirmed when considering ultimate truth because it happens many times each day for the non-enlightened.
Each time the mind believes & acts with craving in terms of an imagined "I", "me", "mine", "you" etc, that is 're-birth'; the mental production of the view of 'beings' ('satta'). '
Ajahn Chah said:
''Becoming'' (bhava) means ''the sphere of birth.'' Sensual desire is BORN at sights, sounds, tastes, smells, feelings and thoughts,
IDENTIFYING with these things. The mind holds fast and is stuck to
sensuality....Bhava is the preliminary condition for birth. Wherever
birth takes place, that's bhava. For example, suppose we had an
orchard of apple trees that we were particularly fond of. That's a
bhava for us if we don't reflect with wisdom. How so? Suppose our
orchard contained a hundred or a thousand apple trees... it doesn't
really matter what kind of trees they are, just so long as we consider
them to be ''our own'' trees... then we are going to be ''born'' as a
''worm'' in every single one of those trees. We bore into every one,
even though our human body is still back there in the house, we send
out ''tentacles'' into every one of those trees. Now, how do we know
that it's a bhava? It's a bhava (sphere of existence) because of our
clinging to the idea that those trees are our own, that that orchard
is our own. If someone were to take an ax and cut one of the trees
down, the owner over there in the house ''dies'' along with the tree.
He gets furious, and has to go and set things right, to fight and
maybe even kill over it. That quarreling is the ''birth.'' The
''sphere of birth'' is the orchard of trees that we cling to as our
own. We are ''born'' right at the point where we consider them to be
our own, born from that bhava. Even if we had a thousand apple trees,
if someone were to cut down just one it'd be like cutting the owner
down. Whatever we cling to we are born right there, we exist right
there. We are born as soon as we ''know.'' This is knowing through
not-knowing: we know that someone has cut down one of our trees. But
we don't know that those trees are not really ours. This is called
''knowing through not-knowing.'' We are bound to be born into that