The phrase "a more sincere" is correct and usable in written English.
It can be used when comparing the level of sincerity between two or more subjects or actions.
Example: "I appreciate your honesty, but I was hoping for a more sincere response to my question."
Alternatives: "a greater sincerity" or "a deeper sincerity".
Then, in a more sincere tone, he added that he was helping make Mr. Baldwin's "dream come true".
Perhaps a more sincere effort at environmental sustainability comes from Rolls-Royce, which introduced the 102EX, an electric version of its Phantom sedan.
There can scarcely have been a more sincere and heartfelt performance of a football chant that is always capable of prompting goosebumps regardless of one's football allegiances.
"We don't need the scholarship and monument," said Chun Choon Ja, 62. "We want a more sincere apology, not a vague statement of regret, from the U.S. government".
Speaking in the visual language of the modern world, the pope is able to convey a more sincere and dramatic apology than Vatican protocol normally allows.
She eventually became convinced that it was the better choice and found that covering her face was a more sincere attempt to obey God than to merely cover her hair.
"He's been a lot more sincere, a lot less sarcastic.
I might not agree with all she says, but she's a hell of a lot more sincere than Clinton.
I'm sure that with a bit of imagination, the organisers could have found someone a little more sincere, and with a little more genuine connection to the events of late 1980s Russia, to host Gorby's big day.
(Anderson Jill Sobulee (Tuesday and Wednesday) Before Katy Perry, Ms. Sobule penned a far more sincere "I Kissed a Girl".
The company says the drastic move comes from a rethinking of its overall purpose as it looks to make the process of sharing beautifully curated photo stories a private affair that is a bit more sincere.
