Sorry this is late, but 50 years ago, CBS aired S05E15 "Thanks For The Honeymoon".
Toni (Patty Duke) is a woman looking for a deal from DA Manicote (Glenn Cannon), who considers her "a monster." She is a witness to a murder that could bring down a big fish in the organized crime on the Islands.
Toni tells McGarrett and Manicote about King Manola (Lane Bradford) killing Victor Delgado (Kenneth Ing) in cold blood. She's willing to testify to what she saw but she wants something in return. She requests the charges against herself and her boyfriend Marty Walker (Larry Kert) to be lessened considerably. On top of that, she's pregnant and wants to marry Marty in a real church along with a full weekend for their honeymoon at a top resort.
Of course, Manola receives word that Toni not only witnessed Delgado's murder but she's willing to send Manola up the river for it. He doesn't sit still for this and why we see the newlyweds under heavy police guard. Manola is able to get one of his guys in for an assassination attempt. They're only half successful in killing Marty but Toni survives a cyanide poisoning in the honeymoon suite.
While McGarrett is trying to contain the pair, he has a visit from an old flame, Margo (Carol Lawrence). Margo is a free-lance photographer who Toni wanted to photograph her wedding because Margo is well known to the "big magazines." Margo and McGarrett get close in the course of the episode but it's cut short due to the assassination attempt. Talk about killing the mood.
When Toni is told the bad news, she screams her head off. While she was planning to back out at the last minute of testifying against Manola, Marty's death seals a lot of fates.
Mr. Mike does a much better job in his review: https://www.fiveohomepage.com/5-0log5.htm#111
This episode is well done but not one of my favorites. I do enjoy the scenery of the resort. I can also appreciate the acting as well. Patty Duke is playing against type and does a really good job.
Other than that, I can take or leave this episode. There's nothing that really stands out to me except Duke's performance.
Regardless, Happy 50th, "Thanks For The Honeymoon"!!