I think the closest word to the meaning of pues can be "well" , example: Pues no lo tengo claro= Well It´s not clear to me

The connector PUES is used in spanish in several ways. At the beginning of the sentence can be used to emphasize the meaning of the sentence. For example: It's my birthday and I invited all my work colleagues to my party. I invited you as well, but I don't appreciate you. (and I expected you to refuse my invitation) ME -Hola Rach, mañana celebro mi cumpleaños, podrás venir? YOU -Pues no lo tengo muy claro. I asked you tu come to my party but I expect you to refuse, and you know I dont want you to come to my party. Beeing more rude, you can answer "Pues no!" Sometimes "Pues" in the beginning of the sentence can be translated as weel and sometimes not. I'm sorry for my english. Espero que mi respuesta te haya servido, un saludo.

En este caso, se podría traducir como "It is not clear to me" o "I don't completely understand" http://forum.wordreference.com/showthread.php?t=272500&langid=24