Is there a sure way how to DV to Phoenixmon?

If you mean 100% chance then no, you should get your stats fairly high, avoid mistakes and battle a few times if you want to get him. Oh yeah, if you have a tamer level of 10 then he's easy as hell to get as well.

only easy as hell to get if you get the correct champions, and get good stats/conditions without getting the requirements for anither ultimate - then its 50/50 chance of either one of those ultimates being gotten instead
I can never seem to get Birdramon, and the one time I got unimon he had pathetic stats (I was contantly trying to recruit Monochromon, as you will remember Dramon - you know I still haven't got him? ) so I couldn't digivolve him!
Out of all the rare ultimates (H-Kabiterimon, MegaSeadramon, Phoenixmon), I have only ever had MegaSeadramon once and that's it!

My seven year old brother have had Phoenixmon and Megaseadramon.

For me Birdramon was really annoying, when I tried Numemon, he/she came out. When I tried Greymon, he/she came out. But I like him now, cause it's not problem to me if I choose random egg.

Shit, speaking today is just big problem for me, don't care about possible bad sayings.