could
The Italian word 'potrebbe' is a conditional verb typically used in a way analogous to 'could' in English. It translates to 'he/she/it could' and is often used to express possibility, suggest solutions or ask polite questions. In conversational Italian, 'potrebbe' is suitable for most contexts where 'could' would be used in English.
It could be the best choice.
In this sentence, 'potrebbe' is used to speculate that something has the potential to be the best choice. The auxiliary 'essere' is used together with 'potrebbe' to form the conditional mood.
I don't know if he could come.
Here, 'potrebbe' is used to express uncertainty, implied by the phrase 'I don't know'. It is used with the verb 'venire' which means 'to come'.
It might rain tomorrow.
In this example, 'potrebbe' is used to indicate the potential for something to happen in the future, in this case, the possibility of rain tomorrow.