"become insecure" is correct and usable in written English.
You can use it when you want to describe someone feeling unsure of themselves or their situation. Example: After losing her job, Sarah began to feel insecure about her financial future.
"They just become insecure.
Then I become insecure about that.
Work for millions has become insecure and stressful.
New hires with deep areas of expertise can become insecure when they suddenly feel like beginners.
He did become insecure and jealous at times but this was normal for the specific situation.
Once the secret key is exposed in identity-based signatures, all signatures generated from this secret key will become insecure.
However, in 1947 came independence and the creation of Pakistan, and the future of the Indian princes, upon whom the musicians were traditionally reliant, became insecure.
I wonder if, given that role, and the sacking from Lancôme soon afterwards, she herself became insecure about her advancing years?
If a system lets a few people do only very simple things—such as checking whether a product is available the risks can be managed; but if it lets a lot of people do general inquiries it becomes insecure.
Anderson's Rule means you cannot construct a database with scale, functionality and security because if you design a large system for ease of access it becomes insecure, while if you make it watertight it becomes impossible to use.
Flutie maintains the real problem was that Johnson became insecure as the city of Buffalo, and to some extent, the nation, embraced him when he returned to the N.F.L. in 1998 and became remarkably successful.
