As per the Ramanand Sagar Serial during Sita swayamvar, Ravana along with Rama and other kings visited Swayamvar. But none other than Rama was able to lift the Shiva Dhanush. Is it true?
The details regarding the Swayamvara of Sita (avatar of Goddess Lakshmi), are mentioned in two chapters as under, in the Valmiki Ramayana:-
No mention of Ravana attending the Swayamvara of Sita is given in the references mentioned above.
Infact, Ravana was not aware of the very existence of Sri Rama(avatar of God Visnu) or Sita(avatar of Goddess Lakshmi) prior to the meeting of his sister Shuurpanakha with Sri Rama in the Dandaka forest(description of this event is given in Book III : Aranya Kanda - The Forest Trek, Chapter [Sarga] 17)
So as per Valmiki Ramayana- Ravana did not attend the Swayamvara of Sita.
Further,as to who all could possibly lift the bow of God Shiva(which Sri Rama alone succeeded in doing at the Swayamvara, with ease), the below mentioned description is relevant:-
न एतत् सुर गणाः सर्वे स असुरा न च राक्षसाः | गंधर्व यक्ष प्रवराः स किन्नर महोरगाः || १-६७-९
क्व गतिः मानुषाणाम् च धनुषो अस्य प्रपूरणे | आरोपणे समायोगे वेपने तोलने अपि वा || १-६७-१०
None in all the assemblages of gods, inclusive of demigods, demons, gandharva-s, yaksha-s, kinnaraa-s, or reptilian demigods, is capable enough to take aim with this bow and all are rendered incapable... and then, in brandishing this bow for a proper grip, or in bracing its bowstring to the other end, or in twitching the bowstring for its tautness, or in placing the arrow on bowstring at a proper place for a proper stretchability, or even in taking a good aim with it... what will be that capability of one from among humans... [1-1-9, 10]
In other words-nobody could lift the bow of God Shiva except Sri Rama(avatar of God Vishnu), and God Shiva himself.
As mentioned in the other answer Ravana was not present in the Swayamvara of Sita Devi as per the Valmiki Ramayana. I am sharing another reference that corroborates the same and is from towards the end of Devi Bhagawatam 3rd Book Chap. 28:
- O beautiful! My two brothers Khara and Dûsana have been killed in this forest; and being urged by my sister I have come here.
64-65. Now leave your this man-husband, residing in the forest as a pauper, devoid of fortune and wealth; and worship me as a husband. O fair one! I am Râvana, the king of kings; you now become my lord.
- O daughter of Janaka! I am the lord of the Regents of the quarters; and yet I bow my head down to your lotus feet; better accept me and fulfil my desires today.
67-68. Formerly I asked of you from your father, the king Janaka; but he then said, that he had laid a pledge, ‘Whoever will break the S’iva’s bow will marry my daughter.’ The Bhagvân Rudra is my Guru; hence I feared to break his bow, and therefore I was not present in your Svayamvara. But from that time my mind is always thinking of you and is in a state of bereavement for you.
- O beautiful one! Hearing now that you are residing in this forest, I, impelled by my previous fascination for you, have now come hither; and you better now crown my labour with success.”
So as shared above even though Ravana was aware of the Swayamvara he did not participate in it out of fear of Lord Shiva.