It depends on the meaning of those four words,and you can divide the word into two parts. For example in the phrase"请你好好对她“can be divided into"请你/好好/对她。" So 请and the first好should be turned into second tone.

The correct one should sound like qíng nǐ háo hǎo duì tā But Chinese sometimes tends to pronounce it as qíng nǐ hǎo hāo duì tā

I just wanna figure the problem out in the answer given by sky6363. "qíng nǐ hǎo hāo duì tā" when two word have the same pronunciation 3th, we'd like to change the pronounciation of the first word to 2ed tones-"qǐng to qíng",but, if these words conbine to a single word, we usually pronounce the second word with 1st tones-"hǎo to hāo"-with lighter accent.

http://www.italki.com/entry/171321