The phrase "I had never thought that" is correct and usable in written English. You can use it when expressing surprise about something that you previously had no prior knowledge of or expectations for. Example: "I had never thought that the cold winter could be so beautiful."
Anyway, I had never thought that masturbation was a sin.
"I had never thought that isis would kill Jim," he admits.
"I had never thought that I would be involved in narrative structures," Mr. Braxton said.
When I wrote the book on cancer, I had never thought that Ken Burns would make a film about it.
"I had never thought that much about the Confederate flag because I grew up in California," he said, alluding to a segment on persistent controversy around the symbol.
"I usually see them going back and forth but I had never thought that so important a person was living inside the house".
I feel guilty that I've never thought that way before.
It is like the apocryphal Kissinger line about a telephone number for Europe: I have never thought that meant Washington was longing to call Europe for advice.
"It's reassuring that Peter reads," Sonny Mehta said, "but I've never thought that was the most important thing.
"I have never thought that was the way to proceed," said Archbishop Wuerl, who is confronted with this question nearly each week.
I've never thought that, as they say, you eat little children".
I love the desktop app, it’s always running on my Mac. Ludwig is the best English buddy, it answers my 100 queries per day and stays cool.
Cristina Valenza
Retail Lead Linguist @ Apple Inc.