Stative verbs are used in the gerund form as second verbs, not in continuous tenses.
I love knowing that I've helped someone understand a point in English.
When two verbs are together, depending on the first verb, the second verb might be in the full or bare infinitive, a gerund, or to + gerund.
I want to believe it's true.
Let me believe in you, if no one else will.
I love knowing I've helped someone.
I look forward to understanding computers better, with your help.
Stative verbs as gerunds can start a sentence.
Believing in yourself is necessary to succeed in life.
From the source http://www.myenglishteacher.net/gerunds.html :
"Even stative verbs (those verbs that almost never have -ing) can be turned into gerunds. A native speaker of English would NEVER say I am believing you. However, a native speaker could say"
"Believing in God is important."
"Believing, here, is a gerund. It is NOT a verb. Believing in God is a gerund phrase."
To qualify the source, because of a comment made, being a native speaker of English is no guarantee that the language will be used correctly. The obvious implication of the statement in the quote is a native speaker who speaks educated English.
Note: Some so-called stative verbs can be used in a continuous tense, but with a different meaning. For example: I see you now. I'm seeing the doctor tomorrow.