The usual effect of title insurance is that you have the guarantee of the title insurance company that the seller in fact is the owner of the property. Important exceptions may be listed in the policy, however. One trouble with title insurance policies is that they are not written in plain English. Any title problem which the insurance company discovers will be listed as an exception in the policy. There are always a few exceptions listed, no matter how solid the title is.
Some exceptions are harmless and others are serious problems.
The only way to know for sure what it all means is to consult your lawyer and have him or her review the policy. Do this before the closing. After the closing is usually too late. In some transactions, such as a purchase from a private party on a contract for deed, title insurance may not be available, or it may be so expensive that the cost is prohibitive. In such circumstances you should find a competent real estate attorney and request a title opinion.