Liddell & Scott reference the Greek word makran in order to explain molis, the idea of being 'a great way off'.
Thayer translates molis as 'with difficulty' or 'not readily'.
Luke uses the word in connection with a nautical difficulty related to wind conditions when sailing under Crete, they hardly (molis) passed it.
But there is nothing in Paul's words here, or in Paul's words anywhere, that would lead us to suppose that salvation, in and of itself, as administered by God almighty through his Son Jesus Christ and through his own Holy Spirit, is in any way unreliable, probable or uncertain.
But also, nowhere is it suggested that this is an easy path. Far from it, much exhortation is required, in every single apostolic epistle, to ensure that those who have once believed the gospel maintain their path right through to the end, that is to say, all the way to eternal glory, despite persecutions, afflictions and many trials of various kinds, which will perfect them and make them complete.
Overall, the idea is that of something that is desirable to be attained, valuable to be possessed, but is not expected to be an easy, trivial, superficial matter.
It will take the investment of all one can gather, as the merchant who sold all that he had in order to obtain a single pearl of great price, Matthew 35:46.
It will require being separate from all others, that one might be married to just one, Revelation 14:4.
It will require hating father, and mother, and wife, and children, and brethren, and sisters, yea, and one's own life also, Luke 14:26.
It may well require that one take joyfully the spoiling of one's goods, knowing in yourselves that ye have in heaven a better and an enduring substance, Hebrews 10:34.
It will necessitate that I keep under my body, and bring it into subjection: lest that by any means, when I have preached to others, I myself should be a castaway, 1 Corinthians 9:27.
But through all this, and much more, there is no doubt that One stands above, ready to save, ready to chastise, ready to correct, ready to purge, ready to purify and ready to heal, Psalm 85:9, Hebrews 7:25.
For in all these things, and many more, indeed, in all these things we are more than conquerors through him that loved us, Romans 8:37.
For this is the victory and this is the certainty, to look unto Jesus the author and finisher of our faith; who for the joy that was set before him endured the cross, despising the shame, and is set down at the right hand of the throne of God, Hebrews 12:2.
For it was no easy path for Him.
Right to the end, he endured, and only at the very end, through sufferings beyond imagination, did he triumph and cry :
It is finished ! . . . . . . . John 19:30.
All references are to the KJV.