Presumably you have some piece of player code that initiates a jump when the player presses the right button:
You can change this to something like this:
var make_player_jump := false
if Input.is_action_just_pressed("jump") or make_player_jump:
make_player_jump = false
Then simply set
make_player_jump = true when a collision is detected between the player and the specific object, and the player will be forced to jump on the next frame.