I am thinking of booking a two night stay plus a 2 night Halong crusie with this hotel. I have read great reviews on property. The only concern I have is that they require a deposit of US$300 for the arrangement. Is this a common practise? They suggested doing this through Western Union or charging my credit card or direct deposit into their bank account. If I do decide to pay, which one is a more secure way to do it?

It is common practice to ask for a deposit. The most secure way to make a deposit is via your credit card. You also have certain protections by using your credit card - protection against fraudulent use of your card as well as protection in case the company is unable to deliver on your reservations

I stayed at HE 2 just recently. They are a very reliable, trustworthy group. I did not have to make any deposits, but then again I was just booking a hotel room -- no other arrangements.
There have been threads on Trip Advisor recently about this, which leads me to think they may have changed their policy. That said, $300 is quite a large deposit and you might want to discuss with them lowering the deposit and definitely have very clear the cancellation terms.
They are just the nicest people and the hotel is very nice for a 3-star property. We stayed in the junior suite and i would recommend that.

Alison,
What hotel do you recommend in Hanoi? We are looking for mid-price range. You are so knowledgeable that I am just asking you directly! Thanks much!

alison, thanks for your information. I just wrote to Mr.Dan the manager, asking him to adjust the amount of the deposit

missViv, you will get more answers if you post your question separately under a descriptive title "Hotel recs in Hanoi" or some such and if you specify exactly what you mean by midrange. Everyone's idea is different. Do you want US$100 per night or US$50 per night for instance?

Miss Viv, when we were there end of June, Hanoi Elegance 2 junior suite was $75. You can check out my review on Trip Advisor. It's a very nice 3 star property. The problem with Hanoi and HCMC is that there is a VERY steep price increase going from 3 stars to 4 or 5 stars. We were pleased with this.
My full trip report discusses all the hotels where we stayed.

hi,
the common is about 30% of the total. Through Western Union is high fee, you can check with Xoom.com, online transfer and cheaper .