1. 'Will see' is only used alongside a pronoun, for example 'I will see', 'he will see', 'they will see', etc. This is the simple future tense and is used to say that something will happen for certain. 2. 'We'll see' is also simple future (we will see), but is used in English as an expression meaning either 'maybe' as a response to a question, or to refer to a situation that perhaps will happen, but that we (people in general) will have to wait to see whether it occurs or not. 3. 'Time will tell' is also a phrasal expression, and means exactly the same thing as 'we'll see' - when talking about a situation that may or may not occur. Hope this helps!!

To add to Becki's answer, when you use "time will tell" or "we'll see", the next word will be "if" or "whether". I can't think of any other options right now. e.g "Time will tell / We'll see if West Ham United will win the football league this year." "Time will tell / we'll see whether or not oil prices rise to 2013 levels again"

the last two can be used as a response to a question on their own. The first cannot.