Spanish does not usually distinguish between B and V sounds — they are pronounced the same. Anything between a B and a V will be fine. In general, the sound is closer to English B at the beginning of a phrase, or if your lips are already closed, like after M or N (pronounced M before another labial in most accents). For example, the following phrase: Viene el invierno. In other positions, especially between vowels, B and V are softer, sounding closer to English V (but without biting your lip - your upper and lower lips should come close, without touching each other): La abuela viene. Also, note that voiced consonants in Latin (and Slavic) languages need to be fully voiced (your vocal cords need to vibrate from the very start of the sound), unlike in most Chinese varieties.

Hi Edwin: It will depend on who is pronouncing the word. In my case I would pronounce favor with /b/. Usually we would pronounce /b/ . If I use /v/ now is because my mother Spanish language got contaminated with English or other languages like French, Portuguese, German, etc., where there is a distinction between /b/ and /v/. From a Phonetic point of view, you will be understood whether you use /b/ or /v/. In Spanish these two sounds represent one phoneme [b]. Best regards, Antonio

As Phil said, we pronounce "V" and"B" exactly the same in Spanish! So, for example, "Ben" (the name) and "ven" (come), are pronounced exactly the same! I hope it makes sense, otherwise don't hesitate in asking another question, we'll be happy to answer! :D