Student or Learner
Are these two sentences both fine?
I think I won't get married for another 4 to 5 years to come.
I think I won't get married in 4 to 5 years to come.
"I don't think I will ... " is the way we normally say "I think I won't ..."
Numerals under 10 should be spelled out in sentences.
"Four or five" is better than "Four to five". You are making an approximation. "Four to five" means that you seem to be sure that is will occur between four years and five years from now.
"to come" is unnecessary.
"in four or five years to come" isn't right.
Not getting married "for four or five years" is almost the opposite of not getting married "in four or five years." In the first, you get married after four or five years; in the second you don't.