LOS ANGELES, Feb. 22 – Leslie Van Houten walked into her third trial for the Charles Manson-led murders of a Los Angeles grocer and his wife wearing a broad smile she said was due to nervousness rather than optimism over the trial’s outcome.

Dressed in a white sweater and brown checked skirt, Miss Van Houten was hardly recognizable as the obscenity-shouting Charles Manson follower who refused to show remorse during her first trial eight years ago for the 1969 murders of Leno and Rosemary LaBianca.

The two were found stabbed to death in their home Aug. 10, 1969 — one day after the grisly murders of actress Sharon Tate and four friends, in which Miss Van Houten was charged with conspiracy.

The 75 prospective jurors who crowded into the courtroom for jury selection on the trial’s opening day Tuesday showed surprise when Superior Court Judge Gordon Ringer announced the case.

Ringer asked if any panelist knew Miss Van Houten, the attorneys or any principals in the case, and asked the attorneys to exclude one woman who said she did.

“I am an acquaintance of Leslie’s parents,” said Minnie M. Mosher of south Arcadia. Miss Van Houten was a former homecoming princess at nearby Monrovia High School.

The lawyers agreed to excuse Mrs. Mosher, although defense attorney Maxwell Keith said he was doing so “reluctantly.”

The trial was expected to last four months.

Earlier, Miss Van Houten pleaded with a crowd of reporters and cameramen to let her proceed into the courtroom.

Asked why she was smiling, the slim brunette said, “I’m a little nervous about being late. I always smile when I’m nervous.”

One similarity with Miss Van Houten’s previous trials was expected to be the testimony of former Manson follower Linda Kasabian, who testified in the earlier trials in exchange for immunity from prosecution.

Miss Van Houten said she had received an offer of immunity in exchange for turning state’s evidence at the original trial, “but I wasn’t into self-survival enough to take it.”

Miss Van Houten, 28, was freed from jail for the first time in eight years last December on $200,000 bail. She had been held at the Sybil Brand Institute for Women since last summer, when her second trial was declared a mistrial.

Miss Van Houten said she has been spending her time traveling throughout California and typing college students’ “theses and what have you” in the evenings to earn extra cash. She has been mainly dependent on family and friends for support.

“I’ve been meeting with family and friends, mostly to catch up on their lives that I missed,” she said. “My brothers have been married, and I’ve met their wives.”