Pleasant VS. Fun

So it's common to find a sentence like this:

It's fun for me to play tennis.
OR
Playing tennis is fun for me.

But can we replace the word "fun" with "pleasant"?

To me, it sounds wierd.

Playing tennis is pleasant for me.

It's pleasant for me to play tennis.

Maybe you can tell me how the word pleasant is used, in contrast to how fun is used. Maybe telling me what contexts the word "pleasant" is used would help me understand.

Pleasantly yours,

beanbag