He acted believably sincere.    From Wordnet, Princeton University. 

Verb (used without object) : Only if one believes in something can one act purposefully.    From Dictionary.com. 

It’s very difficult to write a sociopathic character believably from a first-person perspective.    From Wordnik.com.  [Superhero Nation: how to write superhero novels and comic books » Open Writing Forum] Reference

Rudy has to move toward them, too, and believably.    From Wordnik.com.  [Rudy?] Reference

None of which can believably act to save their lives.    From Wordnik.com.  [Flixnjoystix.com! » Bobert’s 30 Days of Halloween Horror Continues!] Reference

Is it a matter of who tells the story more believably here?.    From Wordnik.com.  [CNN Transcript Jan 3, 2002] Reference

Now it is the job of the Republicans to believably offer it.    From Wordnik.com.  [Ethnic Politics in Our Enlightened Post-Racial Society] Reference

That hijacking signal was sent out, believably by the pilot.    From Wordnik.com.  [CNN Transcript Oct 3, 2006] Reference

Thirteen people dead, believably from a blown tire in Texas.    From Wordnik.com.  [CNN Transcript Aug 8, 2008] Reference

It's hard to pull off a villain who is believably pure evil.    From Wordnik.com.  [MIND MELD: Bad Guys We Love to Hate: The Best Literary Villains in SF/F/H] Reference

You almost come off believably as being one of their clients.    From Wordnik.com.  [There Is A Difference Between Evil And Just Absurdly Profitable] Reference

But she did push it past the point of believably at some points.    From Wordnik.com.  [CNN Transcript Mar 22, 2002] Reference

And you have to tell this story believably and with no loose threads.    From Wordnik.com.  [Ariston Anderson: Salman Rushdie and the Legend of the MOTH] Reference

I think certain people at Sony Entertainment believably helpful in this.    From Wordnik.com.  [CNN Transcript Sep 1, 2005] Reference

Cole stopped there, hoping he'd sounded believably vague about the details.    From Wordnik.com.  [The Missing Hour]

Forget global warming, Hamaker believably predicts the next ice age is coming.    From Wordnik.com.  [Organic Gardener's Composting] Reference

Who could possibly walk that kind of tightrope and still believably woo Julia?.    From Wordnik.com.  [Single Person's Movie: Conspiracy Theory] Reference

The girl's brother and sister died earlier this week, believably from the virus.    From Wordnik.com.  [CNN Transcript Jan 6, 2006] Reference

I am very much a believer in telling a story honestly, emotionally and believably.    From Wordnik.com.  [Melissa Silverstein: Interview with Kimberly Peirce, Director of Stop-Loss] Reference

His staff reported, not quite believably, that he was hiking the Appalachian Trail.    From Wordnik.com.  [Nikki Haley goes from small-time agitator to credible candidate for S.C. governor] Reference

Your proposals on corporate trade policies are more believably but disappointingly weak.    From Wordnik.com.  [The DNC Platform: Belief You Can Change In] Reference

Of course not; and it now seems that his favourite group is more believably the Bee Gees.    From Wordnik.com.  [Archive 2008-05-01] Reference

She could make anything appear and be believably realistic, complete with sound and smell.    From Wordnik.com.  [Question Quest]

Another good point about this novel is that it is believably set in a working class environment.    From Wordnik.com.  [Archive 2005-06-01] Reference

The destroyed city motif has been pulled off much more believably in games such as Resistance 2.    From Wordnik.com.  [Flixnjoystix.com! » FlixnJoystix Presents: Metaldy’s Meanderings! A Few Reasons Why…Videogame Graphics Are Overrated!] Reference

Yet it was extremely difficult to lie believably in front of someone as perceptive as Truzenzuzex.    From Wordnik.com.  [The End of The Matter]

Still, if there is one person who could believably pull off an upset, it might be Leighton Meester.    From Wordnik.com.  [If We Had An Emmy Ballot...] Reference

They are very different in tone, but they believably exist in the same fictional world (or worlds).    From Wordnik.com.  ["Torchwood" is Tops on BBC America] Reference

An established type (by which is meant that they could believably play the same role over and over again).    From Wordnik.com.  ['The Star Machine'] Reference

Miguel Ferrer is believably abrasive as the executive producer out for "" kick-ass television '' at any cost.    From Wordnik.com.  [News With A Laugh Track] Reference

Fran never looked terrific, and was, much more believably, always involved in those fad diets that seem so ridiculous.    From Wordnik.com.  [French Vanilla Death - Seconda Parte] Reference

Insisted believably he was a fan of Matt and his comment really reflected on the song's suitability for Matt, not Matt.    From Wordnik.com.  [Michael Giltz: American Idol -- Top 36 Round Two: The Winners!] Reference

Perhaps I should have tried harder to make him understand but he could be unbelievably stubborn, un believably unforgiving.    From Wordnik.com.  [A Time to Dream]

The horses are believably portrayed by six well-hung men in chestnut body suits, horse-shaped masks, and hoofs of woven wire.    From Wordnik.com.  [Regina Weinreich: Equus in East Hampton] Reference

It believably depicted real folks 'problems with powerful insights into vital issues seldom mentioned on network news programs.    From Wordnik.com.  [CNN Transcript Oct 20, 2006] Reference

Hendrix succeeds almost uniformly in blending spy-caper action with mind-boggling discourse quite believably and non-lumpishly.    From Wordnik.com.  [Asimov's Science Fiction]

A 2006 affair will probably kill you in a 2008 election because it happened too recently for you to have believably redeemed yourself.    From Wordnik.com.  [Bill Folman: I'm Going To Sue John Edwards For Plagiarism] Reference

Like Schindler's List, this is also great moviemaking that puts you believably inside a concentration camp, this time along with POWs.    From Wordnik.com.  [The O'Reilly Factor]