If it bends easily, it's probably not going to provide the level of protection needed on the trail. The top of the boot should be stiff to hold the ankle in place and provide it with good support. Good boots are either waterproof, or are capable of being waterproofed with special waterproofing solutions. I would avoid fabric boots that are not waterproof. While it's possible to treat non-waterproof fabric boots with liquid silicone, it generally doesn't waterproof the boot enough to be useful.
Wet feet cause blisters.
Stick with waterproof fabric boots, or leather boots that can be treated with Sno-seal, beeswax solution, or other more durable waterproofing solutions. Good boots are heavy enough for their intended use. If good boots are positively out of the question due to price, athletic shoes are always an option. But keep in mind that people have severely sprained ankles in athletic shoes, or in some cases, broken ankles in athletic shoes. Athletic shoes can not be waterproofed either.