The phrase "would doubtlessly be" is grammatically correct and can be used in written English.
It is typically used to express certainty or confidence in something happening in the future. Here is an example of how it could be used in a sentence: "After extensive training and practice, John's performance at the competition would doubtlessly be excellent."
They warned that the coming decade would doubtlessly be "the most fiscally irresponsible in our nation's history," unless the president and Congress somehow lose their cut-taxes-and-spend enthusiasm.
'BALLET MÉCANIQUE' The American avant-garde composer George Antheil (above in 1927), the self-proclaimed "bad boy of music" who died in 1959, would doubtlessly be thrilled by Saturday's performance of his "Ballet Mécanique" by a 25-piece automated orchestra created by the League of Electronic Musical Urban Robots.
'BALLET M?ANIQUE' The American avant-garde composer George Antheil (above in 1927), the self-proclaimed "bad boy of music" who died in 1959, would doubtlessly be thrilled by Saturday's performance of his "Ballet M nique" by a 25-piece automated orchestra created by the League of Electronic Musical Urban Robots.
These shindigs were mostly organized by someone's guilty boarding school mom (or, as she was formally known, the "silly old twat"), who, if you sliced down the middle, would doubtlessly be made entirely of jam and cream sponge.
Such an autonomous civic practice, providing basic funding for Europe's unemployed youth, would doubtlessly cost a pile, but just a fraction of the zeros which have been, and are probably going to be, swallowed up by the rescue of the banks.
If she had never set up a personal server she would doubtlessly now be in a stronger political position, but the one she currently occupies is probably strong enough.
Immigrants without documentation would be allowed to (eventually -- the "path" would doubtlessly have been a long one) apply for and receive legal status, which would allow them to legally work and pay taxes.
Had they not included him they would doubtlessly have been accused of discriminating against the Traveller community: it was a lose-lose situation.
While the main event will doubtlessly be good television (pretty much a guarantee, with Trump at the center podium), I wouldn't be surprised if the truly extremist quotes actually come out of the kids' table debate.
Every slight, real or imagined, will doubtlessly be magnified.
Our overwhelming lead will doubtlessly be modified as other major industrial nations rise.
