Feel deeply, when do you say this?
I think it is used on its own .
But when ?
When you have strong emotions in general ?
When you feel attached to someone emotionally ?
Could it be followed by a preposition + object.like. I feel deeply for my son.

Thank you

Question

Feel deeply, when do you say this?
I think it is used on its own .
But when ?
When you have strong emotions in general ?
When you feel attached to someone  emotionally ?
Could it be followed by a preposition + object.like. I feel deeply for my son.

Thank you

Answer

When you have strong emotions in general ? Yes.
When you feel attached to someone emotionally ? Yes.
Could it be followed by a preposition + object like: I feel deeply for my son. Yes.

Good job!=)
It just means what you are feeling is intense. You can also say I feel deeply/strongly about fidelity in marriage.