"Sometimes I wonder" means that sometimes (on occasion) I contemplate or think deeply about a topic. For example: "Sometimes I wonder about the poor state of the world." This would mean that I think about the issues of poverty or hate around the world and ask myself "why is it like this?" To wonder (in the sense that you are asking), means that you most likely will not have an answer to the questions but you still think about them anyway.

sometimes = as vezes i wonder = eu imagino ou penso. traduzindo ficaria assim: "As vezes eu imagino" ou dependendo do contexto da conversa "As vezes eu penso".

Oi Guilherme. Essa expressão aí vai significar "Às vezes imagino..." Não tem mais do que isso, na verdade!