What “facts” of Mary’s supposed assumption are you referring to? It has already be established that it is not known what happened to her. There are no “facts” that can be shown to support any assumption.
What about the fact that it is part of Sacred Tradition?
“If the Holy Virgin had died and was buried, her falling asleep would have been surrounded with honour, death would have found her pure, and her crown would have been a virginal one…Had she been martyred according to what is written: ‘Thine own soul a sword shall pierce’, then she would shine gloriously among the martyrs, and her holy body would have been declared blessed; for by her, did light come to the world."
Epiphanius, Panarion, 78:23 (A.D. 377).
“[T]he Apostles took up her body on a bier and placed it in a tomb; and they guarded it, expecting the Lord to come. And behold, again the Lord stood by them; and the holy body having been received, He commanded that it be taken in a cloud into paradise: where now, rejoined to the soul, [Mary] rejoices with the Lord’s chosen ones…” Gregory of Tours, Eight Books of Miracles, 1:4 (inter A.D. 575-593).
“As the most glorious Mother of Christ, our Savior and God and the giver of life and immortality, has been endowed with life by him, she has received an eternal incorruptibility of the body together with him who has raised her up from the tomb and has taken her up to himself in a way known only to him.” Modestus of Jerusalem, Encomium in dormitionnem Sanctissimae Dominae nostrae Deiparae semperque Virginis Mariae (PG 86-II,3306),(ante A.D. 634).
“It was fitting …that the most holy-body of Mary, God-bearing body, receptacle of God, divinised, incorruptible, illuminated by divine grace and full glory …should be entrusted to the earth for a little while and raised up to heaven in glory, with her soul pleasing to God.” Theoteknos of Livias, Homily on the Assumption (ante A.D. 650).
“You are she who, as it is written, appears in beauty, and your virginal body is all holy, all chaste, entirely the dwelling place of God, so that it is henceforth completely exempt from dissolution into dust. Though still human, it is changed into the heavenly life of incorruptibility, truly living and glorious, undamaged and sharing in perfect life.” Germanus of Constantinople, Sermon I (PG 98,346), (ante A.D. 733).