Ok, for starters I don't really think Gray likes Juvia (though I wished he did, they are so awesome and cute together) and for Natsu and Lucy, it's a high chance, but we have also seen how Erza counts on Natsu alot so that could also be a possibility, Jellal and Erza, they are a VERY good couple, but as you can see so far, Jellal is locked up (;~; HOW UNFAIR!) so I'm not sure how to make of that, and I think it SHOULD be Jelza XD Other than that, I think those are my opinions XD
My answer is most likely.
NaLu (NatsuxLucy) has a very high possibility, from what I have seen there relationship has grew, Natsu saved Lucy a couple times (seen her naked to which was pretty funny) and even though Lissana came back from Edolas, Natsu still spent most of his time with Lucy. Also there are many NaLu scenes/parts in the Anime/Manga.
GrUvia (GrayxJuvia)
Like NaLu, Gray saved Juvia a couple of times, and one time sacrificing his life (if you don't read the Manga than I won't spoil by what I meant). There is defiantly some sort of connection between the two, not like NaLu or JeRza, but still.
JeRza (JellalxErza)
There is a lot of reasons that JeRza will happen, in that Anime, and more to come from the Manga. I don't really explain here cause if you watched the Anime than you should probably know.
In the end I do think that those three couples will happen at some point.
Ok for graylu, there is a possibility although at first gray is a little irritated. If you continue reading e manga u will understand.
For nalu probably not,( jus a suggestion, if u jus started watching fairy tail I advise u not to read the spoilers)
WARNING SPOILERS:
natsu shared a close relationship with erza as shown in chapter 355 where they bathe together. Also in the recent chapter, natsu and lisanna were naked together in tataros jail. Also jellal was presumably killed in chapter 368.
It will end with Gruvia because Gray and Juvia are so close and Juvia already loves Gray. Gray just has to realize his feelings for her. Jelza is a large possibility but Jellal thinks that Erza deserves better than him. Natlu is possible but small because Natsu and Lucy have more of a friend relationship.
