I hope we can be friends.

I would suggest saying "I hope we can become friends" to someone you just met.

It is never necessary to join 'some' and 'time' together to make an adverb 'sometime'. Some people join them together and invent rules about when to use this word, but it is completely necessary. If you leave them as two separate words, it will always be correct. For example: We must meet up for a drink some time. Why don't you come over and visit us some time? Let's go and watch a movie some time. Forget about 'sometime'. You don't need it.

I hope we can become friends. I hope we will become friends.

Hello