Look on the bright side.

This is an expression that means "Think positively." People use this expression when they're talking to someone who's having a problem. After saying "Look on the bright side", the speaker then says something good that the person who's having the problem can be happy about. Here are some other examples of things that you could say to someone who lost his or her job:

Look on the bright side. At least you won't have to wake up early to go to work now.

Look on the bright side. You're young, you've got a good degree. I'm sure you'll have a new job in no time.

(someone) can justify (doing something)

Being able to "justify" an action or decision means that you're able to feel or explain why it's OK.

There are some things that you can't justify:

I like them, but I just can't justify spending that much on a pair of jeans.

But if you can think of a reason why it's OK, then your're able to justify it:

I could justify spending that much on them if I was able to wear them to work as well as on the weekends.

In general, "justifying" ideas means thinking of reasons to explain why you did something, after you already did it or wanted to do it. Usually "justifying" actions and decisions has a little bit of a negative feeling attached to it:

Don't try to justify what you did! You knew that what you were doing was wrong.