When we say shema followed by emes veyatziv or emes v'emunah there are reasons brought down not to make a hefsek between Hash-m... and "emes" and even treat it like being in middle of a paragraph.
If one says shema not with brachos k"sh (whether early in am or al hamitah) why does one finish with the word "emes"?
Was it always like that? (Ie didnt people say shema before emes vyatziv was written ehich i think was in times of ezra based on seder hayom)?
1) (a) The Shulchan Aruch (Orach Chaim 61:3) writes that there are 245 words in Keri'as Shema, and since a person has 248 limbs, the Chazan repeats the three words "Hash-m Elokeichem Emes" to complete the number of words to 248.
The Rema there cites an opinion that someone who says Keri'as Shema alone (and will not hear the Chazan's additional three words) should say "E-l Melech Ne'eman" before the beginning of Shema, and these three words thereby achieve the aim of reaching 248 words.
(b) Therefore, just saying the word "Emes" is not sufficient, but one needs to say three words. If it is an individual who says the Shema, the words he says are "E-l Melech Ne'eman."
(c) The Mishnah Berurah (OC 46:31) mentions saying all three paragraphs of Shema early in the morning only if one is afraid that the community is going to say Shema later than the proper time.
(d) Similarly, the Mishnah Berurah (OC 239:1) writes that in Keri'as Shema before going to sleep, it is good to say all of the Parshiyos, which constitute 248 words (including "E-l Melech Ne'eman"), which guard the 248 limbs.
2) Your question about Shema before the time of Ezra is an interesting one. There is an opinion in the Gemara (Berachos 21a) that Keri'as Shema is a Mitzvah d'Rabanan, while Emes v'Yatziv is a Torah Mitzvah (because it contains mention of Yetzi'as Mitzrayim). If one takes that literally, then one could argue that if there is no Emes v'Yatziv there is no Shema, but then one has to explain how could it be that Emes v'Yatziv was written only in the time of Ezra. In short, this question requires further study.