A guy likes me, but I am not sure if I like him and he proposed. What should I say?

It is a really simple yet complicated question

Reason:

If you like him and you don’t know – then you need to take time to evaluate which may be construed as not interested
If you don’t like him and you tell him upfront, you might risk hurting him badly
If you don’t like him and you don’t tell him upfront but with diplomatic gesturing – you might end up hurting both the people involved

Considering this, it would be better if you sit down and evaluate

How well do you know what you need
How well do you know what you want
How well do you know the person
Will your positive or negative answer impact the person adversely
Post your actions – will the topic be put to rest or it might take some ugly turn?

Think about it

You are a best person to know the situation more than anybody else telling you.

Use your time, energy & emotions to think and come to a solution.

Hope this helps

God Bless!