“I wouldn't mind seeing her again.”
You're a single guy. You met a girl at your friend's party and hit it off with her. Now your friend is asking what you think of her. You say this because you would like to go on a date with her.
I wouldn't mind seeing her again.
To "not mind" something means to be OK with it, or to not be bothered by it:
A: Sorry it's taking so long.
B: No problem. I don't mind waiting.
You use the phrase "I wouldn't mind ___ing" when you want to do something, but you don't want to seem too eager.
A: So... what should we do now?
B: I wouldn't mind getting a cup of coffee.
In the example above, even if the speaker is really interested in this girl and excited about seeing her again, he probably wants to act cool in front of his friend.
The meaning of "I wouldn't mind ___" can change depending on which word that you stress, though. If you don't really want to do something, you can stress the word "mind":
I wouldn't mind going..."
This means that you don't really want to go, but you will go if necessary.
There are multiple meanings for "see (someone". One is to simply see someone with your eyes:
I saw her at the farmer's market yesterday.
But you can also use the phrase "seeing someone" to mean "dating". For example, if you're interested in a person you can ask:
Are you seeing anyone?
This means, "Do you have a boyfriend / girlfriend?"
I'd like to see you again sometime.
This means "I'd like to go on another date with you."
The expressions using "see" sound cooler and more natural than directly using words like "date", "boyfriend", "girlfriend", and so on.