As a person who has had several part time assistants in the past I will offer you a simple piece of advise that should apply regardless of what country the assistant is located.
If you have an assistant, personal or business, virtual or otherwise, and you don't trust that person with this type of information, get a different assistant.
An assistant is someone who is supposed to make your life easier by off loading work. Modifying your records before sending them every month sounds like you are creating more work for yourself not less. Either take the leap of faith to trust your assistant or go somewhere else. An assistant that you feel you have to edit crucial information from is less than useful.
That being said, there is no fundamental reason to believe that an operation in the Philippines or anywhere else is any more or less trustworthy than an operation in your native country. However, what is at issue is the legal framework around your relationship and in particular your recourse if something goes wrong. If you and your virtual assistant are both located in the US you would have an easier time collecting damages should something go wrong.
I suggest you evaluate your level of comfort for risk vs. cost. If you feel that the risk is too high to use an overseas service versus the savings, then find someone in the states to do this work. Depending on your needs and comfort you might want to seek out a CPA or other licensed/bonded professional. Yes the cost might be higher however you might find that it is worth it for your own piece of mind.
As a side note you might even consider finding a local part-time assistant. This can often be more useful than a virtual assistant and may not cost as much as you think.
If you can live without someone being bonded. (or are willing to pay for the bonding fee) yourself, depending on your market and needs you may be able to find an existing highly qualified EA or other person that wants some after hours work.
If you are in a college town, finance, accounting or legal majors make great assistants. They will usually work a couple hours a week for "beer money", they have flexible schedules and are glad to have something pertinent to their degree to put on their resume when they graduate. Just be prepared to replace them every few years as they move on to real jobs.