One of the facts that show that the Gospels of the New Testament are true is that there are a body of testamony that they all include.  One of these inclusions is the story of the woman that annoints Jesus with perfume.  Jesus said, "Truly I say to you, wherever the gospel is preached in the whole world, what this woman has done will also be spoken of in memory of her.” Only the 4 Gospels of the New testament have this story.

 Matthew 26:6-13
"Now when Jesus was in Bethany, at the home of Simon the leper, 7 a woman came to Him with an alabaster vial of very costly perfume, and she poured it on His head as He reclined at the table. 8 But the disciples were indignant when they saw this, and said, “Why this waste? 9 For this perfume might have been sold for a high price and the money given to the poor.” 10 But Jesus, aware of this, said to them, “Why do you bother the woman? For she has done a good deed to Me. 11 For you always have the poor with you; but you do not always have Me. 12 For when she poured this perfume on My body, she did it to prepare Me for burial. 13 Truly I say to you, wherever this gospel is preached in the whole world, what this woman has done will also be spoken of in memory of her.”

Mark 14:3-9
"While He was in Bethany at the home of Simon the leper, and reclining at the table, there came a woman with an alabaster vial of very costly perfume of pure [a]nard; and she broke the vial and poured it over His head. 4 But some were indignantly remarking to one another, “Why has this perfume been wasted? 5 For this perfume might have been sold for over three hundred [b]denarii, and the money given to the poor.” And they were scolding her. 6 But Jesus said, “Let her alone; why do you bother her? She has done a good deed to Me. 7 For you always have the poor with you, and whenever you wish you can do good to them; but you do not always have Me. 8 She has done what she could; she has anointed My body beforehand for the burial. 9 Truly I say to you, wherever the gospel is preached in the whole world, what this woman has done will also be spoken of in memory of her.”

Luke 7:36-50
"Now one of the Pharisees was requesting Him to [a]dine with him, and He entered the Pharisee’s house and reclined at the table. 37 And there was a woman in the city who was a [b]sinner; and when she learned that He was reclining at the table in the Pharisee’s house, she brought an alabaster vial of perfume, 38 and standing behind Him at His feet, weeping, she began to wet His feet with her tears, and kept wiping them with the hair of her head, and kissing His feet and anointing them with the perfume. 39 Now when the Pharisee who had invited Him saw this, he said to himself, “If this man were a prophet He would know who and what sort of person this woman is who is touching Him, that she is a [c]sinner.”
"And Jesus answered him, “Simon, I have something to say to you.” And he [d]replied, “Say it, Teacher.” 41 “A moneylender had two debtors: one owed five hundred [e]denarii, and the other fifty. 42 When they were unable to repay, he graciously forgave them both. So which of them will love him more?” 43 Simon answered and said, “I suppose the one whom he forgave more.” And He said to him, “You have judged correctly.” 44 Turning toward the woman, He said to Simon, “Do you see this woman? I entered your house; you gave Me no water for My feet, but she has wet My feet with her tears and wiped them with her hair. 45 You gave Me no kiss; but she, since the time I came in, has not ceased to kiss My feet.
46 You did not anoint My head with oil, but she anointed My feet with perfume. 47 For this reason I say to you, her sins, which are many, have been forgiven, for she loved much; but he who is forgiven little, loves little.” 48 Then He said to her, “Your sins have been forgiven.” 49 Those who were reclining at the table with Him began to say [f]to themselves, “Who is this man who even forgives sins?” 50 And He said to the woman, “Your faith has saved you; go in peace.”

John 12:1-8
"Jesus, therefore, six days before the Passover, came to Bethany where Lazarus was, whom Jesus had raised from the dead. 2 So they made Him a supper there, and Martha was serving; but Lazarus was one of those reclining at the table with Him. 3 Mary then took a [a]pound of very costly perfume of pure nard, and anointed the feet of Jesus and wiped His feet with her hair; and the house was filled with the fragrance of the perfume. 4 But Judas Iscariot, one of His disciples, who was intending to [b]betray Him, *said, 5 “Why was this perfume not sold for [c]three hundred denarii and given to poor people?” 6 Now he said this, not because he was concerned about the poor, but because he was a thief, and as he had the money box, he used to pilfer what was put into it. 7 Therefore Jesus said, “Let her alone, so that she may keep [d]it for the day of My burial. 8 For you always have the poor with you, but you do not always have Me.”

Since the gospel should be based on Jesus' very words, if a "gospel" does not have the story of the woman that annointed Jesus with perfume, you can be certain that it is a false gospel.