On the Mount of Olives on the night before his death, did Jesus really experience fear of death?
Since Jesus was true man, he truly experienced fear of death on the Mount of Olives.
With the same human strength that we all possess, Jesus had to fight in order to consent interiorly to the Father's will that he give his life for the life of the world. Abandoned in his darkest hour by everyone, even his friends, Jesus managed after a struggle to say Yes. "My Father, if this [cup] cannot pass unless I drink it, your will be done." (YOUCAT question 100)
Dig Deeper: CCC section (612) and other references here.
Part 1: The Profession of Faith (26 - 1065)
Section 2: The Profession of the Christian Faith (185 - 1065)
Chapter 2: I Believe in Jesus Christ, the Only Son of God (422 - 682)
Article 4: "Jesus Christ suffered under Pontius Pilate, was crucified, died and was buried" (571 - 630)
Paragraph 2: Jesus Died Crucified (595 - 623)
III. CHRIST OFFERED HIMSELF TO HIS FATHER FOR OUR SINS ⇡
The agony at Gethsemani ⇡
The cup of the New Covenant, which Jesus anticipated when he offered himself at the Last Supper, is afterwards accepted by him from his Father's hands in his agony in the garden at Gethsemani,434 making himself "obedient unto death". Jesus prays: "My Father, if it be possible, let this cup pass from me..."435 Thus he expresses the horror that death represented for his human nature. Like ours, his human nature is destined for eternal life; but unlike ours, it is perfectly exempt from sin, the cause of death.436 Above all, his human nature has been assumed by the divine person of the "Author of life", the "Living One".437 By accepting in his human will that the Father's will be done, he accepts his death as redemptive, for "he himself bore our sins in his body on the tree."438
434.
435.
Phil 2:8; Mt 26:39; cf. Heb 5:7-8.
436.
437.
Cf. Acts 3:15; Rev 1:17; Jn 1:4; 5:26.
438.
1 Pet 2:24; cf. Mt 26:42.