Okay, worldly pleasant feeling is a feeling of pleasure arising from a sense contact. It's sometimes very difficult to let go of our attachment to pleasant sensory experiences unless we know that a sense of happiness and peace can come from different areas in our life - say from inner happiness. An example of a pleasant worldly feeling is the feeling of being loved by others, when a person likes you, when a person praises you.
An example of a pleasant spiritual feeling is when you are able to have Compassion and Lovingkindness for yourself, and be able to actually have Compassion and Lovingkindness for others. This gives a sense of happiness that is not so dependent on other people's opinions of you, but more on how you give this wish to others. So if you are in great need sometimes of other people's love, it can be pleasant when we are getting it, but it also has the capacity to change and be unpleasant when we are not getting it. However with pleasant spiritual feeling, that feeling of having an open heart and having Compassion and Lovingkindness to others whether they like you or not, is not so dependent on other people. And if we put in the right causes it is much more within our power to reach.
The same with Sympathetic Joy. Sympathetic Joy is the ability to have joy with our own good qualities and the ability to have joy with others' good qualities; it's an ability to have joy rather than fall into jealousy, inferiority or conceit.
Sometimes the capacity for other people to feel happy with us is expressed, and when we get that expression from somebody else, it feels really good. That's a type of pleasant worldly feeling. However if we are able to take happiness with our own good qualities that is a pleasant spiritual feeling, a spiritual happiness. It is a recognition of our good qualities and the capacity to feel Sympathetic Joy with them, not feeling so threatened by the good qualities of others - and that is more under your power to control.
So with pleasant worldly feelings - like praise, fame, pleasure and gain - when we have some we see that it is very nice, but they also have the capacity to turn into suffering when we don't get them; so they are undependable. This is why we prefer to be able to lessen our dependence, gradually, on this type of happiness - and to depend on spiritual types of happiness which is more under our power to control, and which is more within our capacity to reach, if we know the right causes for its arising.