Today would be a good day to point out the difference between "principles" and "promises."
A principle is "a rule of thumb." In general, if you do X you will get Y. If X is something good, Y will be something good. If X is something bad, Y will also be something bad. But there are also what we call "exceptions to the rule." Once in a great while there will come along a situation when X may be good, but a "bad" Y will result.
For example, in general, as a 'rule of thumb' if you take your car to a trusted mechanic and he checks it all over and makes any necessary repairs you will have no car problems on your trip. That's the rule or principle. But once in a great while it will happen that you still find yourself stalled on the side of the road 400 miles from home. That's the exception to the rule.
A promise - when it comes from God - is something you can "take to the bank." In other words, you can trust it completely. It will happen the way He says it will happen. Period. End of sentence. Done deal. When God says, "For God so loved the world that He gave His one and only Son that whoever believes in Him shall not perish, but have eternal life" you can count on it. 100% There will be no exceptions to the rule.
It is extremely important to not view one of God's "principles" as though it were a "promise" from Him. When that "exception to the rule" happens, you will blame God for breaking a promise. Then you will wonder if He can be trusted about anything, and it goes downhill from there. The only problem is, the principle you trust in was never a promise.
Although there are some promises in the book of Proverbs, the majority of the statements are principles. Rules of thumb. We get into big trouble when we put them in God's mouth as promises. A great example is verse six.
Train a child in the way he should go,
and when he is old he will not turn from it.
That is great instruction for parents. Teach your child from as early as possible (day one?) about the way God has designed him or her to live. As a rule of thumb, that's what he or she will be following when they get to be parenting age. But there will be exceptions to the rule. Not all kids who were taught by Christian parents will indeed follow God's ways when they get old. If that happens in your situation, and you viewed that verse as a promise from God, well, you now the result.
Live by God's principles, but know when they are not meant to be promises.